Ok so you would plug in 18 for the x so it would be 6(18)-12 and then 6x18 is 108 and 108-12=96 so your answer is 96
.5(20x-50y+36)-.25(-100x+40y-12)
10x-25y+18+25x-10y+3
35x-25y+18-10y+3
35x-35y+18+3
35x-35y+21
The greatest common divisor of these numbers is 12.
