Question

Use the grouping method to factor the polynomial below completely.

3x3 + 9x2 + 5x + 15
O A. (3x2 + 3)(x+5)
O B. (3x2 + 5)(x + 5)
O C. (3x2 + 3)(x+3)
O D. (3x2 + 5)(x + 3)

Answer 1

The correct answer is D. (3x2 + 5)(x + 3). Here’s how you can use the grouping method to factor the polynomial completely:

Group the first two terms and the last two terms: (3x3 + 9x2) + (5x + 15)

Factor out the greatest common factor from each group: 3x2(x + 3) + 5(x + 3)

Factor out the common binomial factor: (3x2 + 5)(x + 3)

So, the polynomial 3x3 + 9x2 + 5x + 15 can be factored completely as (3x2 + 5)(x + 3).

Hope it helps.