Question

Antonia is factoring the polynomial, which has four terms.

21x3-63x2+15x-45
3[7x3-21x2+5x-15]
3[7x2(x-3)+5(x-3)]
Which is the complete factored form of her polynomial ?

Answer 1

Explanation:

It looks like the terms are:

(7x2 + 5) and (x - 3)

Answer 2

3(x - 3)(7x^2 + 5).

Explanation:

21x3 - 63x2 + 15x - 45

The greatest common factor of the constants is 3, so we have:

3(7x^3 - 21x^2 + 5x - 15)

Now we factor this by grouping:

= 3 [7x^2 (x - 3) + 5(x - 3)

= 3(x - 3)(7x^2 + 5).