7th grade math
posted by saranghae12 .
How would you solve the problem below using the subsitution method?
12x + 4 = 8y
y = x  7
Please explain to me and help. If you could show all the steps, that would help a lot. Thank you.

put the y equation in the first equation.
12x+4=8*(x7)
12x+4=8x56
subtract 8x from each side, subtract 4 from each side.
Then having solved for x, put that into the original y= equation 
Oohhh thank you soo much!!!