Question

System of substitution
Y-9=-x
3x-y=7

Answer 1

1. X = 9 - Y

2. X = 7+y/3

I really hope this helps. :)

Answer 2

3(y-9)-y=7
3y - 27 -y = 7
2y = 34
Y = 17

3(x) -17 = 7
3x = 24
X = 8