Hi Brainiac
y=3x-7
y=2x+1
We need to solve y=3x-7 for y
Now let's start by substitute 3x-7 for y in y=2x+1
y=2x+1
3x-7=2x=1
Now add -2x
3x-7-2x=2x+1-2x
x-7=1
Add 7
x-7+7=1+7
x=8
Our last step is to substitute 8 for x in y=3x-7
y=3x-7
y=(3)(8)-7
y= 24-7
y= 17
Answer : A
I hope that's help:)