Answer:
180=100+3x+x
180=100+4x
180-100=100-100+4x
80=4x
20=x
20
Step-by-step explanation:
3x + 100 + x = 180
or, 4x = 180 - 100
or, 4x = 80
or, x = 80/4
or, x = 20
