Use the grouping method to factor the polynomial below completely.

3x3 + 9x2 + 5x + 15

(3x^2+5) (x+3)

Step-by-step explanation:

The given expression is:

3x3 + 9x2 + 5x + 15

First of all group the first two terms and last two terms:

(3x3 + 9x2) + (5x + 15)

Now factor out the greatest common factor from each group:

3x^2 (x+3) + 5 (x+3)

(3x^2+5) (x+3)

Thus the factors of 3x3 + 9x2 + 5x + 15 are:

(3x^2+5) (x+3) ...

Answer: (3x^2 + 5) (x + 3)

Step-by-step explanation:

B.