How do you solve this? y=-4 y=2x-8

Question

My teacher didn't give me any words along with this equation. Please help.

The equation:

y=-4

y=2x-8

Answer 1

Hello Hailey,

To answer this, we need to substitute one equation into the other. Anytime we have a variable that is the same as another variable (e.g. the two "y"s in this case), we can replace one term with what the other term is equal to. In this case, since we know from the first equation that y = -4 , we can take that and replace the "y" in the second equation with "-4", as they are the same. From there you solve with traditional algebra. When you do this it will look as follows:

y = 2x - 8

substitute -4 for "y"-->

-4 = 2x - 8

add 8 to both sides-->

4 = 2x

divide both sides by 2 -->

2 = x

This is the final answer, and we can report the two answers as y = -4 and x = 2

Hope this helps!

Answer 2

Hailey, seems like you need to solve for x. Here substituting y=-4 in the second equation : -4 = 2x -8 . Solving this gives us 2x = -4 +8 = 4 , which implies x = 2