solve using elimination method -3x+4y=1, -6x+6y=-3

double the first

-6x + 8y = 2
-1 times the 2nd
6x - 6y = 3
add them:
2y = 5
y = 5/2
sub into 1st:
-3x + 4(5/2) = 1
-3x = -9
x=3