[lisaly]

Originally Posted by lisaly

I think there is a much simpler way to do this problem. There are too many opportunities for mistakes with having the same denominator, and there's no need in this problem. If you need me to talk you through it by phone, I'd be happy to help. I've done it many times with my students and their parents when they are struggling at home.

set both y values to equal
-3 1/2 = 3/4x-8
add 8 to both sides

5 1/2 = 3/4x
multiply both sides by 4 to get rid of the denominator
11/2 x 4 =3x
21=3x
x=7

check:
-2.5=3/4x -8
add 8 to both sides

5.5=3/4 x7
5.5=21/4
5.5=5.5

I wrote 5,5 instead of 4.5
4.5 = 3/4x
multiply by 4
18=3x
divide by 3
x=6

without simple calculation errors, this involves less steps. So many people have problems with denominators, and there really is no need to have the same denominators.