Question

Substitutions
1.x + 4y = 6
y = -x + 3

2.x + 2y = 6
x - y = 3

Answer 1

1x + 4 (-×+3) = 6
1× -4× + 12 = 6
-3× = -6
× = 2

2× +2y = 6
× - y = 3
multiply second equation by 2x - 2y = 6
now add equations
4x = 12 so x = 3. substitute 3 - y = 3 so y is 0. check in first equation 2×3 + 2×0 = 6. 6+0= 6