tentukan nilai x nya

a. 180=7x+x+x
180=9x
x=180/9
x=20

b.180=90+4x+5x
180-90=9x
90=9x
x=90/9
x=10

c.180=130+x+x
180-130=2x
50=2x
x=25

A. 180 = 7x + x + x
180 = 9x
180/9 = x
20 = x

B. 180 = 90 + 4x + 5x
180 = 90 + 9x
180-90 = 9x
90 = 9x
90/9 = x
10 = x

C. 180 = 130 + x + x
180 = 130 + 2x
180 - 130 = 2x
50 = 2x
50/2 = x
25 = x