on the grounds that 4x+2y = 12 and x+2y = 6 Do an uncomplicated subtraction 4x+2y-x-2y = 6 (12-6) the 2y's cancel one yet another out 4x-x = 6 3x = x x = 2 plug this into the two equation 2+2y = 6 / 8+2y = 12 2y = 6-2 / 2y = 12-8 2y = 4 / 2y = 4 y =2 / y = 2