Question

Factor 3x3 + 27x2 + 60x.

A. (x + 5)(x + 4)
B. (x + 6)(x + 10)
C. 3x(x + 5)(x + 4)
D. 3x(x + 6)(x + 10)

Answer 1

`\mathrm{C}`

Explanation:

`3x^3 + 27x^2 + 60x`

`3x\left(x^2+9x+20\right)`

`3x[x\left(x+4\right)+5\left(x+4\right)]`

`3x\left(x+4\right)\left(x+5\right)`

Answer 2

3x( x+5) (x+4)

Explanation:

3x^3 + 27x^2 + 60x.

Factor out the greatest common factor

3x( x^2 +9x+20)

Now factor inside the parentheses

What two numbers multiply to 20 and add to 9

5*4 = 20

5+4 =9

3x( x+5) (x+4)