Solve by substitution:

Question

x-y=3
x+3y=6

This is what I get:
X+3y=6
Y=x-3
X(x-3)=6
2x= 9
2 2
X= 9/2

9/2+3y=6
9/2-9/2+3y= 6-9/2
3y/3= 3/2/3
Y= ½

Answer 1

man, ya gotta check your answer. It does not fit the first equation.

y = x-3, so
x + 3(x-3) = 6
4x = 15
x = 15/4
y = 3/4

Answer 2

thank you