# Math Help - Substitution

1. ## Substitution

It's been awhile since i've done substitution and the notes i've taken seem to make no sense to me. I have a big unit test on Wednesday and am in need of help.

How would I solve this equation in substitution?

x + y = 27
y = 3x +7

I've tried to do this equation numerous times but am unable to do it.

2. Originally Posted by largebabies
It's been awhile since i've done substitution and the notes i've taken seem to make no sense to me. I have a big unit test on Wednesday and am in need of help.

How would I solve this equation in substitution?

x + y = 27
y = 3x +7

I've tried to do this equation numerous times but am unable to do it.