Question

What is the mABC? help plz

Answer 1

mB=12-x

Explanation:

mA+mC+mB=180

9x-12+5x+24+mB=180

9x+5x-12+24+mB=180

14x+12+mB=180

14x+mB=180-12

14x+mB=168

x+mB=168÷14

x+mB=12

mB=12-x