tentukan nilai x dan y

c. 2x+40 = x + 80
x = 40
y= 180 - 120 = 60

d. x = 180 - 102 = 78

e. 180 - 7y = 5x
180 - 5x = 80, 5x = 100, x = 20
y = (180 - 100) : 7 = 80/7