Can someone help me please

3

Step-by-step explanation:

Since the triangles are congruent.

The hypotenuses are equal.

13 = 4x + 1

13 - 1 = 4x + 1 - 1

12 = 4x

12/4 = 4x/4

3 = x

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