I need help finding x

x = 6

ΔABC is a  isosceles triangle at A

=> m∠B = m∠C

=> 4x + 56 = 80

⇔ 4x = 80 - 56 = 24

⇔ x = 24/4 = 6

Step-by-step explanation:

hello from mrbilldoesmath!

answer:   x (x+6)^2, choice b

discussion:

factor x out of the equation:

x^3 + 12x^2 + 36x = x (x^2 + 12x + 36).

note that 6+6 = 12 and 6*6 = 36 so the above factors into:

x (x+6)^2

which is choice b

you,

mrb