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3 years ago

If 2x^2 -2y^2 = 72 and if x+y=18 what does x-y equal

2 answers:

7 0

First factor out the 2:

x^2 - y^2 = 36

x^2 - y^2 can be factored into (x+y)(y-y) so:

(x + y)(x - y) = 36

plug in your value:

18 (x-y) = 36 and you should be able to take it from there

Shalnov [3]3 years ago

6 0

2x^2-2y^2=72
divide both sides by 2
x^2-y^2=36
factor difference of 2 perfect squares
(x-y)(x+y)=36
given that x+y=18, subsitute 18 for x+y
(x-y)(18)=36
divide both sides by 18
x-y=2

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weeeeeb [17]

Answer:

$33\frac{3}{4}$

Step-by-step explanation:

3 0

3 years ago

Which ordered pair could not be the coordinates for a clockwise rotation of the point W(-3, 4)?

Eduardwww [97]

Step-by-step explanation:

<em>Look at the picture.</em>

Any pair of choice can be the coordinates of the rotation of the point

W (-3, 4) clockwise.

All points have the same distance from the beginning.

The formula of a distance between the origin and a point (x, y):

$d=\sqrt{x^2+y^2}$

W(-3, 4)

$d=\sqrt{(-3)^2+4^2}=\sqrt{9+16}=\sqrt{25}=5$

(3, -4)

$d=\sqrt{3^2+(-4)^2}=\sqrt{9+16}=\sqrt{25}=5$

(4, 3)

$d=\sqrt{4^2+3^2}=\sqrt{9+16}=\sqrt{25}=5$

(-4, -3)

$d=\sqrt{(-4)^2+(-3)^2}=\sqrt{9+16}=\sqrt{25}=5$

(-4, 3)

$d=\sqrt{(-4)^2+3^2}=\sqrt{9+16}=\sqrt{25}=5$

3 0

3 years ago

Find the standard deviation for each group of data items. Round answers to two decimal places. 7,9,9,15

KonstantinChe [14]

Answer:

Step-by-step explanation:

the calculator I used

http://www.alcula.com/calculators/statistics/standard-deviation/

6 0

3 years ago

What should be added to 780629 so that the sum is exactly divisible by 493?

Leokris [45]

Answer:

283

Step-by-step explanation:

Given problem is based on divisibilityy,

= 780629/493

quotient = 1583

remainder = 210

So,Add 283 with remainder (210) to get 493

= 283+210

= 493

There for 283 should be added to 780629 so that the sum is exactly divisible by 493

7 0

3 years ago

Read 2 more answers

The dot plots show rainfall total for several spring storms in highlands areas an lowlands areas what is the median rainfall for

tankabanditka [31]

*See attached picture showing the dot plots referred to

Answer:

16mm

Step-by-step Explanation:

Given the dot plot showing rainfall for Highlands storms, we can find out the median rainfall for Highlands storms by mere observing the dot plot and locating where the middle value falls within the data set that is represented on the dot plot.

Thus, we have 44 data sets that is being represented on the plot, with one dot representing one data set for rainfall. This means, since the total number of data set is even, our median lies between the 22nd and the 23rd dot or data set that is being plotted.

From the dot plot for Highlands, the 22nd and 23rd dots are 16 and 16 respectively.

Therefore, median rainfall for Highland storms = (16 + 16) ÷ 2 = 16.

8 0

3 years ago

Read 2 more answers