Please answer this question​

see explanation

Step-by-step explanation:

(a)

a × - b ( cancel 3 and 15 and 7 and 21 )

= a × - b

= - ab

(b)

3xy(5x²y² - 4yz) ← multiply each term in the parenthesis by 3xy

= 15x³y³ - 12xy²z

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