Sheila M. answered • 02/10/13

Friendly College Math Professor - understands students' math anxiety

Hi, Shay.

This problem looks like a good candidate for using substitution to solve it.

y = -x + 8

y = x

We can substitute x (from the second equation) in place of y (in the first equation):

x = -x + 8

Now solve the new equation by getting the variable term on only one side:

x = -x + 8

+x +x .

2x = 8

Now divide by 2 on both sides...

2x = 8

2 2

x = 4

This problem is almost done. You need to determine the value of y too. Since y = x, they have the same value. Does your teacher want the answer in ordered pair form (x, y)? If so, my answer is (4, 4).