Question

Solve the following system by any method.

–8x – 8y = 0
–8x + 2y = –20
A. (2, –2)
B. (–2, 2)
C. (2, 2)
D. (0, –2)

Answer 1

We can rearrange the two equations to get x in terms of y.
-8x - 8y = 0
-8y = 8x
x = -y
AND
-8x + 2y = -20
-8x = -20 - 2y
x = y/4 + 2.5

Now we have -y = y/4 + 2.5
By multiplying all by 4 we get:
-4y = y + 10
-5y = 10
y = -2

And because we know that x = -y, x = 2

So the solution is (2,-2) - A.