Question

For the following system, if you isolated y in the first equation to use the Substitution Method, what expression would you substitute into the second equation?

4x − y = 8
2x + 3y = 9

8 − 4x

8 + 4x

−8 + 4x

−8 − 4x

Answer 1

You want to use the first equation to find the value of y, so you want to isolate y in the first equation:
\[4x-y=8\]You could start by adding y to both sides:
\[4x=y+8\]From here you just need to subtract the 8 to get y all by itself.