Question

y=3x+9
Y=2x+6
how do i do this

Answer 1

y = both those things, you can maybe just compare y=y,. or 3x+9 = 2x + 6

Answer 2

or , take (-1) times one of those equations, and then add them together

y + (-y) goes to zero for the left side

Answer 3

Subtract eq 2 from eq 1,
LHS from LHS and RHS from RHS,
We get,
y-y=3x+9-2x-6
0=x+3
Subtract 3 both side
0-3=x+3-3
-3=x
So x=-3