solve the system of equations using elimination 3c - 8d =7 and c + 2d = -7

Answers

Answer 1

Answer:

d=-2 c=-3

Step-by-step explanation:

3c-8d=7

4(c+2d=-7)

3c-8d=7

4c+8d=-28

4c+3c-8d+8d=7-28

7c=-21

c=-3

c+2d=-7

-3+2d=-7

2d=-4

d=-2

Answer 2

Given.

[tex](3c-8d=7)=(c+2d=-7)[/tex]

Multiply 4 to the second equation.

[tex]4(c+2d=-7)[/tex]

[tex]3c+8d=-28[/tex]

Compare the like terms.

[tex]4c+3c-8d+8d=7-28[/tex]

Solve.

[tex]7c=-21[/tex]

Divide 7 to both sides

[tex]\frac{7c}{7}=\frac{-21}{7}[/tex]

[tex]c=-3[/tex]

Substitute (-3) for c into the original second equation.

[tex]c+2d=-7[/tex]

[tex]-3+2d=-7[/tex]

Add (3) to both sides.

[tex](-3+2d=-7)+3[/tex]

[tex]2d=-4[/tex]

Divide (2) to both sides.

[tex]\frac{2d}{2}=\frac{-4}{2}[/tex]

[tex]d=-2[/tex]

Check your work.

[tex]3(-3)-8(-2)=7[/tex]

[tex]-9+16=7[/tex]

[tex]7=7[/tex]

[tex]c+2d=-7[/tex]

[tex]-3+2(-2)=-7[/tex]

[tex]-3-4=-7[/tex]

[tex]-7=-7[/tex]

Therefore your answer is.

[tex]c=-3\\d=-2[/tex]


Related Questions

If you're reproducing a 4 cm x 4 cm picture on a 3 m x 3 m wall, what ratio should you use?

Answers

Answer:

So you can divide by 2 for the picture. 4/2 = 2

So you can get 2 x 2 picture. The ratio would be 1

if you have a variable it would always be

x by x.

If you want to cover whole wall multiply by 4/3 on the 4 x 4 picture

The original needs to be scaled up by a factor of 75.

Given that, reproducing a 4 cm × 4 cm picture on a 3 m × 3 m wall.

We need to find what ratio we should use.

What is the ratio?

Ratio, in math, is a term that is used to compare two or more numbers. It is used to indicate how big or small a quantity is when compared to another.

We know that 1 m=100cm, then 3 m=300 cm.

The picture on the wall is (300 cm)/(4 cm) = 75 times as large in each dimension as the original.

Therefore, the original needs to be scaled up by a factor of 75.

To learn more about the ratio visit:

https://brainly.com/question/13419413.

#SPJ2

How would you go on dividing 7/893​

Answers

Answer:

0.00783874

Step-by-step explanation:

7/893= 0.00783874

I just put it in the calculator  

what is the definition for congruent arcs

Answers

Answer:

"If two arcs are both equal in measure and they're segments of congruent circles, then they're congruent arcs"

Step-by-step explanation:

If x = 2 and y = 4, then (2x + 3y) ÷ 4 - 2 =
A) 10
B) 9
C) 8
D) 2
WILL MARK BRAINLIEST

Answers

Answer:

Answer is option d) 2

Step-by-step explanation:

[tex]given \: that \: x = 2 \: \: \: and \: \: \: y = 4 \\ value \: of \: \frac{2x + 3y}{4} - 2 \\ = \frac{2(2) + 3(4)}{4} - 2 \\ = \frac{4 + 12}{4} - 2 \\ = \frac{16}{4} - 2 \\ = 4 - 2 \\ = 2[/tex]

HAVE A NICE DAY!

THANKS FOR GIVING ME THE OPPORTUNITY TO ANSWER YOUR QUESTION.

For the given expression (2x + 3y) ÷ 4 - 2, If x = 2 and y = 4, the value of expression is, 2

What are expressions?

An expression is a sentence with at least two numbers or variables having mathematical operation. Math operations can be addition, subtraction, multiplication, division.

For example, 2x+3

Given that,

The expression, (2x + 3y)/4 - 2

The value of expression, when  x = 2 and y = 4

⇒ (2×2 + 3×4)/4 - 2

⇒  (4+12)/4 -2

⇒   16/4  - 2

⇒  2

Hence, the value of expression is 2

To know more about Expressions check:

brainly.com/question/16804733

#SPJ2

Given the points (-2,-4) and (-3,-5) what is the slope

Answers

Answer:

1/1

Step-by-step explanation:

Joshua has $4,200 to invest for college. If Joshua invests $4,200 for 3 years and earns $630, what is the simple interest rate? Joshua's goal is to have $5,000 after 4 years. Is this possible if he invests with a rate of return of 6%? Explain.

Answers

Answer: Yes it's possible for Joshua to meet his goal of having $5,000 after 4 years.

Step-by-step explanation:

From the question, Joshua has $4,200 to invest for college which he invests $4,200 for 3 years and earns $630.

Interest = (Principal × Rate × Time)/100

630 = (4200 × R × 3)/100

630 = 12600R/100

12600R = 630 × 100

12600R = 63000

Interest rate =63000/12600 = 5%

Joshua's goal is to have $5,000 after 4 years. Is this possible if he invests with a rate of return of 6%?

Interest = (Principal × Rate × Time)/100

Interest = (4200 × 6 × 4)/100

= 100800/100

= $1008

At the end of 4 years, Joshua will have:

= $4200 + $1008

= $5208

Yes it's possible.

I need help ASAP I shall give brainlyist (idk how to spell)

Answers

Answer:

12 cm

Step-by-step explanation:

The volume of a cylinder is given by

V = pi r^2 h

We know the diameter is 6 so the radius is d/2 = 6/2 = 3

108 pi = pi (3)^2 h

108 pi = 9pi h

Divide each side by 9pi

108 pi /9pi = 9pi h/9pi

12 = h

Answer:

12cm in height

Step-by-step explanation:

While training for an Ironman competition, Johnson swam 0.86 km, biked for 22.4 km, and ran 4.25 km. Johnson completed this routine twice a week. How far did Johnson travel in one week while training, in meters?

Answers

Answer:

55020 metres

Step-by-step explanation:

Johnson swam 0.86 km, biked for 22.4 km, and ran 4.25 km. He did this twice a week.

To find the total distance traveled in one week in metres, we first add up the distances and multiply by 2 and then convert to metres.

The sum of the distances is:

0.86 + 22.4 + 4.25 = 27.51 km

Multiply by 2:

27.51 * 2 = 55.02 km

1 km = 1000 metres

55.02 km = 55.02 * 1000 = 55020 metres

He traveled 55020 metres while training.

find the perimeter of diameter 3.5 cm​

Answers

Answer: I am assuming it’s of a circle? So the answer would be rounded to 11.

Step-by-step explanation:

is x^2 + y^2 = 5 a function

Answers

Answer:yes

Step-by-step explanation:

Finn's pool leaked a total of 3.5 liters in 4 days. What rational number represents the average change in water volume each day?

Answers

Answer:

The rational number representing the average change in the volume of water each day is:

[tex]\frac{0.875 liters}{1 day}[/tex]

Step-by-step explanation:

Rational numbers are those that can be represented as the quotient of two integers. That is, rational numbers can be represented by a fraction [tex]\frac{a}{b}[/tex], where a is the numerator and b is the denominator that must be other than zero. To express the set of these numbers, mathematicians use a capital Q.

In this case we know that Finn's pool leaked a total 3.5 L in 4 days, so the rate can be written as:

[tex]\frac{3.5 liters}{4 days}[/tex]

Now you must make this division or quotient, where the denominator will be 1 because you must know the number of liters drained per day:

[tex]\frac{3.5 liters}{4 days}=\frac{0.875 liters}{1 day}[/tex]

So the rational number representing the average change in the volume of water each day is:

[tex]\frac{0.875 liters}{1 day}[/tex]

PLEASE HELP WILL MARK BRAINLIEST

Eight students were asked how many books they read last summer. Their answers are shown in the line plot below.



Find the range and the mode for the data.

(a)range:
(b)mode:

Answers

Answer:

(a). Range is 6 (b). Mode is 5.75

Step-by-step explanation:

Finding range: Subtract the smallest value (2) from the largest value (8).

Finding mode: Add all the values (for each "x" you add the value that it corresponds to) and then divide them by the number of x's.

Which fraction is less than the fraction represented by the model?

Answers

Answer:

fraction represented by model = 5/8

fraction less than model = 2/4

The fraction that is less than the fraction represented by the model is 2/4, the correct option is D.

What is a Fraction?

A fraction is a number that is the part of the whole.

It is represented in the form of p/q, where q is not equal to zero.

The figure has a circle in which sections have been divided.

There are some shaded sections and some non-shaded sections.

The number of shaded section is 5.

The number of non-shaded section is 3.

The total sections are 8.

The fraction that is represented by the model is 5/8.

The model shown is a visual way to represent and understand fractions.

The fraction = 0.625

The fraction in the options are,

3/4 = 0.75

11/16 = 0.6875

13/16 = 0.8125

2/4 = 0.5

0.5 < 0.625

2/4 < 5/8

To know more about Fraction

https://brainly.com/question/10354322

#SPJ5

i need help pls, i would appreciate it !!

Answers

Answer:

a. x = 1.2, b. A = 32.1°

Step-by-step explanation:

1.41²-.75²=x²

a. x = 1.2

sin A = 0.75/1.41

b. A = 32.1°

A circle with center (-1, 2) and radius of 8 has the equation

Answers

Answer:

c)

Step-by-step explanation:

The equation of the circle that has a center (-1, 2) and radius of 8 will be (x + 1)² + (y – 2)² = 64. Then the correct option is D.

What is an equation of a circle?

A circle can be characterized by its center's location and its radius's length.

Let the center of the considered circle be at the (h,k) coordinate.

Let the radius of the circle be 'r' units.

Then, the equation of that circle would be:

(x – h)² + (y – k)² = r²

A circle with center (-1, 2) and radius of 8.

Then the equation of the circle will be

(x – h)² + (y – k)² = r²

(x + 1)² + (y – 2)² = 8²

(x + 1)² + (y – 2)² = 64

Thus, the equation of the circle that has a center (-1, 2) and radius of 8 will be (x + 1)² + (y – 2)² = 64.

Then the correct option is D.

Learn more about the equation of a circle here:

https://brainly.com/question/10165274

#SPJ5

PLEASE HELP MEEEEE ITS VERY UGRENT

Answers

Answer:

4.75

Step-by-step explanation:

u = 10  a = -2  t = 0.5 (half)

need to work out u times t add 0.5 times a times t ^2

so 10 x 0.5 + 0.5 x -2 x 0.25

= 4.75

Answer:

s=4.5 m

Step-by-step explanation:

in the equation s=ut+1/2at squared, u=10, a=-2, and t==1/2. So substitute the given values by the units u, a and t.

[tex]s=ut+\frac{1}{2} at^{2} \\s=10*\frac{1}{2}+-2*\frac{1}{2}^{2}\\ s=5+(-2)*\frac{1}{4}\\ s=5+\frac{-2}{4}\\ s=\frac{5*4-2}{4}\\ s=\frac{20-2}{4}\\ s=\frac{18}{4}\\ s=4.5 m[/tex]

A beverage manufacturer performs a taste-test and discovers that people like their fizzy beverages best when the redius of the bubbles is about 0.7 mm. According to the formula below, what would be the volume of one of these bubbles?

Answers

Answer:

0.267[tex]mm^3[/tex]

Step-by-step explanation:

Radius of the Bubble = 0.7 mm

Volume of the bubble is given by the formula :

[tex]r=\sqrt[3]{\frac{3V}{4\pi } }[/tex]

Taking cube on both sides

[tex]V=\frac{4\pi\times r^3 }{3}\\\\ V=\frac{4\times3.14\times(0.7)^3}{3}\\\\V=\frac{12.56\times 0.064}{3}\\\\ V=\frac{0.804}{3}\\\\V=0.267mm^3[/tex]

perform the indicated operation 5/11 + 9/11​

Answers

Answer:

It would be 14/11

when you make it a mixed number, it'll be 1 3/11

Step-by-step explanation:

You can't simplify it more than 3/11 so

1 3/11

solve the question 2 (3x plus 5) Square - 16 = 0 buy completing the square​

Answers

Answer:

Step-by-step explanation:

Helpp pLZZZZ
Jack can mow the baseball grounds in 2 hours; Mike can mow the same grounds in 3 hours; and Chris can mow the grounds in 4 hours. How long will it take to mow the baseball grounds if Jack, Mike, and Chris work together?
Leave your answer in proper fraction form, then round to 1 decimal place.
Using your rounded answer, how many minutes would that be?

Answers

Answer:

1hr 37min 18 sec

Step-by-step explanation:

Jack can mow the baseball grounds in 6 hours

Jack rate = 1/6 job/hr

-------------------------------

Mike can mow the same grounds in 5 hours

Mike rate = 1/5 job/hr

-------------------------------

Chris can mow the grounds in 4 hours.

Chris rate = 1/4 job/hr

-------------------------------

Together rate = 1/x job/hr

----------------------------------

Equation:

rate + rate + rate = together rate

[ 1/6 + 1/5 + 1/4] = 1/x

x[(5*4 + 6*4+ 6*5)/(6*5*4)] = 1

----

x(74/120) = 1

x = 120/74 = 1.62 hours = 1 hr 37 min 18 sec

A man drove 14 mi directly east from his home, made a left turn at an intersection, and then traveled 3 mi north to his place of work. If a road was made directly from his home to his place of work, what would its distance be to the nearest tenth of a mile?

Answers

This would make a right triangle. Use the Pythagorean theorem to solve.

X = sqrt(14^2+ 3^2)

X = sqrt( 196 + 9)

X = sqrt(205)

X = 14.3178

Rounded = 14.3 miles

The arithmetic mean if ui = xi - 25 / 10 sigma fiui = 20 and sigma fi = 100 is

Answers

Answer:

27

Step-by-step explanation:

Given the formula ui = xi - 25 / 10

Note that the general formula for calculating ui = xi-A/n where;

A = assumed mean

n = class size

On comparison with the given equation, A = 25 and h = 10

Also arithmetic mean  x = A + {h * sigma(fiui) /sigma(fi)} where;

sigma(fiui) = 20 and  sigma fi = 100

Substituting the given value to get the mean x;

x = 25+ (10*20/100)

x = 25 + (200/100)

x = 25 + 2

x = 27

The arithmetic mean is 27

Which choice is equivalent to the fraction below when x is an appropriate value? Hint: Rationalize the denominator and simplify. 5/5+√10x

Answers

Answer:

The equivalent fraction is:   [tex]\frac{5-\sqrt{10x} }{5-2x} }[/tex]

which agrees with the second answer in the list of options

Step-by-step explanation:

Recall that in order to rationalize a denominator of this type (remove the square roots), we need to multiply numerator and denominator of the fraction we have by the conjugate of the binomial. That is, multiply top and bottom of the fraction by the expression:  

[tex]5-\sqrt{10\,x}[/tex]

Therefore we have:

[tex]\frac{5}{5+\sqrt{10\,x} } =\frac{5\,(5-\sqrt{10x} )}{(5+\sqrt{10\,x})\,(5-\sqrt{10x})} =\frac{5\,(5-\sqrt{10x} )}{(25-10x)} }=\frac{5\,(5-\sqrt{10x} )}{5\,(5-2x)} }=\frac{5-\sqrt{10x} }{5-2x} }[/tex]

Then this is the equivalent rationalized expression:

[tex]\frac{5-\sqrt{10x} }{5-2x} }[/tex]

Answer:

B.

Step-by-step explanation:

A P E X

How do i graph the quadratic function f (x)=-(x-3)(x+1)

Answers

Answers:

It's basically Inside, Outside, Outside, Inside. (I. O.O.I.)

Explanations:

Given

[tex]f(x)=-(x-3)(x+1)[/tex]

Distribute the (-1) to (x-3)

[tex]f(x)=(-x+3)(x+1)[/tex]

Now let's work the I. O. O. I.

Inside:

[tex](-x)(x)=-x^2[/tex]

Outside:

[tex](-x)(1)=-x[/tex]

Outside:

[tex](3)(x)=3x[/tex]

Inside:

[tex](3)(1)=3[/tex]

Add both the outsides (-x) and (3x) together

[tex]-x+3x=2x[/tex]

Your new equations is now.

[tex]f(x)=-x^2+2x-3[/tex]

Melanie is walking a path around a circular path to view all of the artwork painted on the cement edge. The circular fountain has a radius of 30 feet. If Melanie only walked around the fountain once, how far did she travel?

Answers

18.8 feet, 59.1 feet to the nearest tenth
Step-by-step explanation:
The diameter is the line drawn that divides the circle into two while the circumference is the perimeter of the circle. Both are a measure of the radius of the circle.
The diameter D = 2r where r is the radius of the circle
The circumference = 2Πr = ΠD where Π = 22/7
Given that the circular fountain has a radius of 9.4 feet
Its diameter =  2 × 9.4 feet = 18.8 feet
The circumference = 22/7 × 18.8 feet
=59.09 feet
≈ 59.1 feet to the nearest tenth

Find the length of the third side to the nearest tenth.
5
1

Answers

Answer:

square root of 26 (sorry couldn't get the symbol)

Step-by-step explanation:

C^2 = A^2 + B^2 (Pythagoras Theorem)

C^2 = 5^2 + 1^2

C^2 = 26

take square root of both sides

C =

[tex] \sqrt{26} [/tex]


Please I need help with this I’m stuck I need to get it right

Answers

Answer:

b

Step-by-step explanation:

Geometric mean is used to determine the scale of objects.

False

True

Answers

The answer to this question is true
the answer to the question is true

A student is given three triangles and must determine which triangles are
congruent. The student is also told that C = D = Y. Which of the
following statements is true? Justify your answer.

Answers

Answer:

the answer is B, because triangle BCA is a rotation of triangle XYZ.

Step-by-step explanation:

Anyone know the answer

Answers

Answer:

3

Step-by-step explanation:

72/9 = 8 ( The quotient of 72 and 9)

8-5 = 3 (Decrease by 5)

Other Questions
Why barren lands are coloured in white? What change did Philip ll make after Unifi in Greece Please help! Correct answer only, please! Jason has the following averages in his math class: homework avg: 80 quiz avg: 84 test avg: 74 final exam: 60 if the teacher weights homework at 20%, quizzes at 30%, tests at 40%, and the final exam at 10%, what is jason's class average? A. 74 B. 77 C. 79 D. 82 The door of the jail being flung open from within, there appeared, in the first place, like a black shadow emerging into sunshine, the grim and grisly presence of the town-beadle, with a sword by his side and his staff of office in his hand.Which best describes the purpose of the words black shadow, grim, grisly, and sword?to impart a sorrowful moodto impart a solemn moodto establish the early morning settingto establish the militant jailhouse setting Albert is a server at an all-you-can-eat sushi restaurant. At one table, the customers ordered 4 child buffets and 1 adult buffet, which cost a total of $86. At another table, the customers ordered 4 child buffets and 3 adult buffets, paying a total of $130. How much does the buffet cost for each child and adult? Can someone help me on these two questions? Which of the following best describes The League of Nations in postwar Europe?O a successful peacekeeping forceO a forum for solving problemsO a weak and ineffective organizationOa group that provoked international distrust please helpFrom an upstairs window, I can see my neighbor's fence. The angle of depression is 7 degrees. If my window is 15 ft off the ground, how far is my neighbor's fence from my house? Round to the nearest whole number, do not include units. Eating disorders are caused by all of the following factors EXCEPT:A. psychological factorsB. genetic factorsC. economic classD. financial factorsPlease select the best answer from the choices provided. OD Are all genes that are passed on advantageous? Why or Why not? Help please.....anyone what activities belong at the top of the physical activity pyramid if the distance from the source is doubled, what will happen to sound intensity Two angles add to 90. The larger angle is 12 more than five times the measure of the smaller angle. Find the measure of the two angles. Tropical rainforests are found between the Tropics of Cancer and Capricorn, 23.5 north and south of the equator. True or false? find the slope of the line through points 8,2 and -1,-4 Name 2 things the samurai had to do to meditate. Which statement is most clearly supported by the information in the chart above? A. Involvement of the U.S. in WWI lasted about 3 yearsB. The United States was better prepared to fight World War I.C. The United States joined World War II at the start of the war.D. World War II had a greater impact on the United States than did WW1. Which number is rational? How was the U.S unprepared for Coronavirus? What could the U.S do in the future to improve