Prove the following statements: (a) For every integer x, if x is even, then for every integer y, xy is even. (b) For every integer x and for every integer y, if x is odd and y is odd then x y is even. (c) For every integer x, if x is odd then x 3 is odd.

Answers

Answer 1

Answer and Step-by-step explanation:

(a) Given that x and y is even, we want to prove that xy is also even.

For x and y to be even, x and y have to be a multiple of 2. Let x = 2k and y = 2p where k and p are real numbers. xy = 2k x 2p = 4kp = 2(2kp). The product is a multiple of 2, this means the number is also even. Hence xy is even when x and y are even.

(b) in reality, if an odd number multiplies and odd number, the result is also an odd number. Therefore, the question is wrong. I assume they wanted to ask for the proof that the product is also odd. If that's the case, then this is the proof:

Given that x and y are odd, we want to prove that xy is odd. For x and y to be odd, they have to be multiples of 2 with 1 added to it. Therefore, suppose x = 2k + 1 and y = 2p + 1 then xy = (2k + 1)(2p + 1) = 4kp + 2k + 2p + 1 = 2(kp + k + p) + 1. Let kp + k + p = q, then we have 2q + 1 which is also odd.

(c) Given that x is odd we want to prove that 3x is also odd. Firstly, we've proven above that xy is odd if x and y are odd. 3 is an odd number and we are told that x is odd. Therefore it follows from the second proof that 3x is also odd.


Related Questions

find the difference.

(4−5y)−2(3.5y−8)

Answers

Answer:

-12y + 20

Step-by-step explanation:

First, you simplify each term:

apply the distributive property:

4 - 5y - 2 (3.5y) - 2 x -8

Multiply 3.5 by -2:

4 - 5y - 2 (3.5y) - 2 x -8

Multiply -2 by -8:

4 - 5y - 7y +16

Next, we simplify by adding terms:

Add 4 + 16:

-5y - 7y + 20

Subtract 7y from 5y:

-12y + 20

Hence the simplified form is -12y + 20

Answer:

-4·(3y-5)

Step-by-step explanation:

Help! Marking Brainliest (Check Screenshot) Please show work, thank you.

Answers

Step-by-step explanation:

Area of Square picture = 20.25 in²

Side lengths of Square picture

= √(20.25 in²) = 4.5 in.

Therefore the dimensions of the picture

is 4.5in by 4.5in.

Josiah and his children went into a grocery store and he bought $15 worth of peaches and mangos. Each peach costs $0.50 and each mango costs $1.50. He bought 2 more mangos than peaches. Graphically solve a system of equations in order to determine the number of peaches, x,x, and the number of mangos, y,y, that Josiah bought.

Answers

Step-by-step explanation:
p = peaches, m = mangos
1.75p + 1.50m = 22
m = p + 6
1.75p + 1.50(p + 6) = 22
1.75p + 1.50p + 9 = 22
1.75p + 1.50p = 22 - 9
3.25p = 13
p = 13 / 3.25
p = 4 <====== she bought 4 peaches
m = p + 6
m = 4 + 6
m = 10 <===== she bought 10 mangos
check...
1.75p + 1.50m = 22
1.75(4) + 1.50(10) = 22
7 + 15 = 22
22 = 22 (correct)

Here is a rectangle.
9 cm
7 cm
Work out the perimeter of the rectangle.

Answers

Answer:

P=32cm

Step-by-step explanation:

Answer: 32

Step-by-step explanation: 9+9 =18

                                             7+7= 14

                                               14+18=32

a piggy bank has $6.95 and contains only nickles and dimes. If there are a total of 91 coins, how many nickles are there

Answers

Answer:

There are 43 nickels in the piggy bank.

Step-by-step explanation:

Given that:

Number of coins = 91

Worth of coins = $6.95 = 6.95*100 = 695 cents

Let,

x be the number of nickles

y be the number of dimes

According to given statement;

x+y=91     Eqn 1

5x+10y=695     Eqn 2

Multiplying Eqn 1 by 5

5x+5y = 455    Eqn 3

Subtracting Eqn 3 from Eqn 2

(5x+10y)-(5x+5y)=695-455

5x+10y-5x-5y=240

5y = 240

[tex]\frac{5y}{5}=\frac{240}{5}[/tex]

y = 48

Putting y=48 in Eqn 1

x+48=91

x=91-48

x= 43

Hence,

There are 43 nickels in the piggy bank.

rob has 7.8 ounces of tuna salad. If she makes three sandwiches with an equal amount of tuna on each, how much tuna does she put on each one?

Answers

Answer:

2.6 tuna

Step-by-step explanation:

Amount of tuna salad rob has = 7.8ounces

Amount of sanndwiches made = 3sandwiches

If she had equal amount of tuna on each sandwiches

Amount of tuna in each = Total amount of tuna/Amount of sandwiches

Amount of tuna in each = 7.8/3

Amount of tuna in each  = 2.6 tuna

Hence she put 2.6 tuna in each sandwiches

Two boats leave the same place at the same time. The first boat heads due north at 10 kilometers per hour. The second boat heads due west at 16 kilometers per hour. After 2.5 hours, how fast is the distance between the boats increasing

Answers

Answer:

18.87 km/hr

Step-by-step explanation:

First boat is heading North with a speed of 10 km/hr.

Second boat is heading West with a speed of 16 km/hr.

Time for which they move = 2.5 hours

To find:

The speed at which the distance is increasing between the two boats.

Solution:

Let the situation be represented by the attached diagram.

Their initial position is represented by point O from where they move towards point A and point B respectively.

[tex]Distance = Speed \times Time[/tex]

[tex]Distance\ OA = 10 \times 2.5 = 25\ km[/tex]

[tex]Distance\ OB = 16 \times 2.5 = 40\ km[/tex]

We can use Pythagorean Theorem to find the distance AB.

AB is the hypotenuse of the right angled [tex]\triangle AOB[/tex].

According to Pythagorean theorem:

[tex]\text{Hypotenuse}^{2} = \text{Base}^{2} + \text{Perpendicular}^{2}\\\Rightarrow AB^{2} = OA^{2} + OB^{2}\\\Rightarrow AB^2 = 25^2 + 40^2\\\Rightarrow AB^2 = 2225^2\\\Rightarrow AB^2 \approx 47.17\ km[/tex]

The speed at which distance is increasing between the two boats is given as:

[tex]\dfrac{47.17}{2.5} \approx 18.87\ km/hr[/tex]

In Miami, Florida, there is an 80% probability of extreme high winds on a specific day. How was this probability most likely determined

Answers

Answer:

80%

Step-by-step explanation:

Since this is an 80% chance we can say that on these days with same conditions, the probability of extreme high winds is 80% of the time in Miami.

Megan picked 15 blueberries on Monday, 35 on Tuesday, and 55 on Wednesday. Based on the pattern, how many blueberries will she pick on Thursday?

Answers

The Amount of blueberries will be 75 on Thursday

The concept of hope is nothing more than giving up. A word that holds no true meaning.

Answers

Answer:

lol fr

Step-by-step explanation:

Answer:

Big pp

Step-by-step explanation:

HELP ONLY ANSWER IF YOU ARE TODALLY SURE I WILL GIVE BRAINLEST TO WHOEVER IS RIGHT WORTH 18 POINTS DON'T JUST ANSWER BUT READ IT THEN ASWESR

Which equation can be used to calculate the area of the shaded triangle in the figure below?

A rectangle is shown with a width of 6 ft and a length of 16 ft. There is a diagonal line through the rectangle, and the bottom half is shaded in grey.

1. 2(16 × 6) = 192 square feet

2. 2(16 + 6) = 44 square feet

3. 1 over 2.(16 × 6) = 48 square feet

4. 1 over 2.(6 + 16) = 11 square feet

Answers

Option 3.
1/2(16x6)=48
1/2(96)=48
1/2(96)=48
48=48

A mix of 32 quarters and dimes totals $6.35. Find the system of equations that would help you answer the question and then find how many quarters (x) and dimes (y) you would have?

Answers

Answer:

21 quarters and 11 dimes = 32 coins

Step-by-step explanation:

x + y = 32

0.25x + 0.10y = 6.35 [take the first equation and make it equal to x]

x = 32 - y [now take this equation and plug it in the above]

0.25 (32-y) + 0.10y = 6.35

8 - 0.25y + 0.10y = 6.35

8 - 0.15y = 6.35  [subtract 8 from both sides]

-0.15y = -1.65 [divide by -0.15 to isolate y]

y = 11 so there are 11 dimes

plug it into the first equation: x + 11 = 32; x = 21 so there are 21 quarters

write an equation in point slope form for the line through the given point with the given slope (-4, -3); m=8

Answers

Answer:

An equation in point-slope form for the line will be:

[tex]y - (-3) = 8 (x - (-4))[/tex]

Please check the attached line graph also.

Step-by-step explanation:

Given

The point (-4, -3)

The slope m = 8

To determine

Write an equation in point slope form for the line.

Using the point-slope form of the line equation

[tex]y-y_1=m\left(x-x_1\right)[/tex]

where

m is the slope of the line(x₁, y₁) is the point

In our case,

(x₁, y₁) = (-4, -3)The slope m = 8

substituting the values m = 8 and the point (-4, -3)

[tex]y-y_1=m\left(x-x_1\right)[/tex]

[tex]y - (-3) = 8 (x - (-4))[/tex]

Therefore, an equation in point-slope form for the line will be:

[tex]y - (-3) = 8 (x - (-4))[/tex]

Please check the attached line graph also.

Valeria's Cupcakes recently sold 3 pumpkin cupcakes and 9 other cupcakes. Considering this data, how many of the next 8 cupcakes sold would you expect to be pumpkin cupcakes? ​

Answers

Answer:  24 Pumpkin cupcakes.

Step-by-step explanation:

We know that:

They recently sold 6 Pumpkin cupcakes and 8 other cupcakes.

Then we can model this with the ratio  6:8

This means that for each 6 Pumpkin cupcakes sold, they also sell 8 of another type of cupcakes.

With this information, if they sell 56

If $600 was placed in a savings account with an interest rate of 0.5%,
find the total amount in the account after 8 years and 3 months (8.25
years)?

Answers

I got it wrong so oof

can u pls help me with this question ​

Answers

Answer:

0.12$ , I'm probably wrong lolol

plz answer my question

Answers

4R+12

When you diffuse (multiply) the 4 to the rest of the number r become 4r and 3 becomes 12 giving you the equivalent of 4r+12

Whenever Jean sees the white streaks left in the sky by an airplane, she excitedly tells her kids it's Buzz Lightyear. One day, her son asked her how fast Buzz could fly. Jean, knowing that Buzz is really an airplane, told him about 500 miles per hour. How many feet per second can Buzz travel? Show your work, friends.

Answers

Answer:

The Buzz can travel 733.33 feet per second.

Step-by-step explanation:

An hour has 60 minutes, each of which has 60 seconds. So one hour has 60*60 = 3600 seconds.

The airplane can fly 500 miles per hour. Each mile has 5280 feet. So the plane can fly 500*5280 = 2640000 feet in one hour.

Per second, we have:

[tex]\frac{2640000}{3600} = 733.33[/tex]

The Buzz can travel 733.33 feet per second.

what percent is a is b? pls help i need it right away

Answers

Do you mean a grade in percentage?

Answer:

what ???????????????????? repost this question

be quick! i will mark the correct one brainliest :)

Answers

Whats the queastion think
abcdefghijklmnopqrstuvwxyz

((11-7)+(14/7)^2)=
A. 4
B. 2
C. 5
D. 8

Answers

the answer is D: 8
lmk if it’s right

What is an equivalent ratio for 7:9

Answers

14:18, 21:27, 28:36, etc...

What is the answer to this ? PLEASE HELP I HAVE 3 minutes

Answers

Answer:

(2, 4)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtract Property of Equality

Algebra I

Solving systems of equations using substitution/elimination

Step-by-step explanation:

Step 1: Define Systems

y = 2x

x = -y + 6

Step 2: Solve for y

Substitution

Substitute in x:                     y = 2(-y + 6)Distribute 2:                         y = -2y + 12Isolate y terms:                    3y = 12Isolate y:                               y = 4

Step 3: Solve for x

Define equation:                    x = -y + 6Substitute in y:                       x = -4 + 6Add:                                        x = 2

HELP ASAP GIVING BRAINLIST

Answers

Step-by-step explanation:

An open circle means that it isn't equal to the number so the sign would either be < or >

The number that the circle is on is -1 so x is either < or > to -1

x is anything to the left to -1 so the inequality would be x< -1

I hope this helps!!!

There are 54 bookshelves in the library
and 3,240 books total.
How many books does
each shelf hold?

Answers

Answer:

60

Step-by-step explanation:

Assuming that all 54 shelves hold the same number of books its just a matter of dividing them (or sharing them equally) on each shelf.

3240 / 54 = 60

Each shelf holds 60 books.

The scholastic assessment test is standardized to be normally distributed with a mean μ=500 and a standard deviation σ=100. What percentage of SAT scores falls
a. between 500 and 600
b. between 400 and 600
c. between 500 and 700
d. between 300 and 700
e. above 600
f. below 300

Answers

Answer:

68.27%.

Step-by-step explanation:

Here we have [tex]\mu=500,\sigma=100[/tex]

Let X shows the SAT score. z-score for X=400 is

[tex]z=\frac{X-\mu}{\sigma}=\frac{400-500}{100}= -1[/tex]

z-score for X=600 is

[tex]z=\frac{X-\mu}{\sigma}=\frac{600-500}{100}=1[/tex]

So the proportion of SAT scores falls between 400 and 600 is

[tex]P(400<X<600)=P(-1<z<1)=0.6827[/tex]

hence, required percentage is 68.27%.

one can use the same method to find the% for all other cases as

well.

If Fran were to paint her living room alone, it would take 6 hours. Her sister Denise
could do the job in 8 hours. How long would it take them working together? If needed,
submit your answer as a fraction reduced to lowest terms.

Please show steps !! my last test for the semester!! 20 points PLEASE!!!

Answers

Answer:

r1 =6

r2 =8

t = ?

[(1/r1) * t] + [(1/r2)*t] = 1

t/6 + t/8 = 1

multiply by common denominator... 24

24 (t/6 + t/8 = 1)

4t + 3t =24

7t = 24

t = 24/7 = 3.4hrs

A scuba diver ascends 5 3/4 feet to the top of a boat platform. The diver then descends 20 1/8 feet by jumping off the boat. Write and evaluate on subtraction expression to show what lever under sea level the scuba currently is

Answers

-15 5/8 feet
5 6/8- 20 1/8

What is a point-slope equation of the line with slope -12 that goes through the point (5, 3)?
A. y- 3 = -12(x - 5)
B. y + 3 = 12(x + 5)
C. y + 3 =-12(x + 5)
D.y-3 = 12(x - 5)​

Answers

Answer:

A. y- 3 = -12(x - 5)

Step-by-step explanation:

a group of hikers is progressing steadily along up uphill trail. the graph shows their elevation

Answers

we can see the graph
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