4x+ y = 12 , 2x+ y = 81) find the unknown (either x or y) that has the same coefficient. - In this example it is y2) Take away the equations from one another so you only have 1 unknown - 2x = 43) Divide by 2, to find the value of x - x = 2 4) substitute the newly found value of x back into one of the equations to find the value of y - (4 x 2) + y = 125) Solve equation - 8 + y = 12 , y = 4