Hi, just wanted to double check your hat this is the right answer or not! if not can you explain to me in comments? !

Yea that can be a good equation. I had this question last year and my teacher said it was ok.

But it can be wrong, I don't really know. Cuz we don't go to the same school.

do i do it on a graph?

step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18