Posted by Laura on .
Hey, I don't undertand how to solve this equation using substitution.
3y = 1/2x + 2
y= x + 9

algebra 
Reiny,
sub the 2nd into the 1st
3y = (1/2)x + 2
3(x+9) = (1/2)x + 2
3x + 27 = (1/2)x + 2
times 2 to get rid of that nasty fraction
6x + 54 = x + 4
7x = 50
x = 50/7
then y = x+9 = 50/7 + 9 = 13/7
check:
in #1:
3y = (1/2)x + 2
LS = 3(13/7) = 39/7
RS =(1/2)(50/7) + 14/7
= 25/7 + 14/7 = 39/7 = LS
my answer is correct.