3x+2y=36
3x-3x+2y=36-3x
2y=36-3x
2y/2=36-3x/2
y=18-1.5x
4x + 13y = 79
4x + 13(18-1.5x)= 79
4x + 13(18) (13)(-1.5x)= 79
4x + 234-19.5x= 79
234-15.5x= 79
234-15.5x-234= 79-234
-15.5x=-155
-15.5x/-15.5=-155/-15.5
x=10
y=18-1.5x
y=18-1.5(10)
y=18-15=3