Question

a + b + c = 180
b = 3a
c = 5a
Whats B

Answer 1

Plug 3a for b and 5a for c

a + 3a + 5a = 180

9a = 180

a = 20

b = 3 x a = 3 x 20

b = 60

Answer 2

sub

b=3a so put 3a for every b
c=5a so put 5a for every c
a+3a+5a=180
9a=180
divide 9 both sides
a=20

b=3a
b=3(20)
b=60