7x+3y=−31 3x+5y=−17

Question

7x+3y=−31

3x+5y=−17

X=

Y=

Answer 1

Start by multiplying each equation in order to get rid of one of the variables (either x, or y). In this case I chose to get rid of x.

3(7x + 3y)=3(-31)

-7(3x + 5y) = -7(-17)

This gives us:

21x + 9y = -93

-21x -35y = 119

Add the two equations together to get:

-26y = 26

Divide by -26 to get y alone:

y = -1

Now we have y! We can plug this value into either equation and get x.

7x + 3(-1) = -31

7x - 3 = -31

7x = -28

x = -4

Now we have x! It is always important to check your work, so now I will plug both x and y into the second equation and make sure it works.

3(-4) + 5(-1) = -17

-12 -5 = -17

-17 = -17

Since -17 = -17 we are all set.