sub
solve for 1 variable
solve for x in seond eqution
divide everybody by 2
x+2y=8
minus 2y
x=8-2y
sub 8-2y for x in other equation
3(8-2y)-2y=12
24-6y-2y=12
24-8y=12
minus 24
-8y=-12
divide -8 both sides
y=3/2
sub
x=8-2y
x=8-2(3/2)
x=8-3
x=5
(5,3/2)