Question

how to solve x+3y=3 and 2x-3y=-12

Answer 1

$x+3y=3\\3y=-x+3\\\\2x-3y=-12\\-3y=-2x-12\\3y=2x+12\\\\-x+3=2x+12=3y\\-9=3x\\-3=x\\\\(-3)+3y=3\\3y=6\\y=2$

x = -3
y = 2

Answer 2

get x on one side then you can use substitution
So, change x+3y=3 to x= -3y+3
Then plug in x to other equation to find y
2(-3y +3)-3y=-12
-6y + 6 -3y = -12
-9y = -18
Divide both sides by negative nine to find y
y = 2
Then plug in to original equation to find x
x + 3(2) = 3
x + 6 = 3
x = -3
So, y = 2 and x = -3