Question

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

−x + 2y = 9
4x + 5y = 9

−9 + 2y

−9 − 2y

9 − 2y

9 + 2y

Answer 1

2y-9

Answer 2

-9+2y. Rearrange the first equation to get -x=9-2y, then times by -1 to get x=-9+2y

Answer 3

or move x to other side to obtain
2y=9+x
then move 9 to left side
2y-9=x
if i see a - on one side i usally try to move it 1st