since one equation has a variable already solved for, we can use that to plug it in to the other equation.
Y has been solved for, plug it into the other one
x + 4(-x+3) =6
x + -4x + 12 = 6
-12. -12
x+(-4x) = -6
-3x = -6
/-3. /-3
x=2
y = -x+3
y = -(2)+3
y=1