Question

completely factor the polynomial.
5x^3+15x^2+5x+15=

Answer 1

You factor it by finding the roots.

Answer 2

well i got it to
5(x^3+3x^2+x+3) but now i'm not sure what to do next

Answer 3

Now try all the POSSIBLE RATIONAL values.

+/- 1 and +/- 3

Answer 4

not sure what you mean by that

Answer 5

If f(x) = x^3+3x^2+x+3,
And if f(3) = 0,
Then 3 is a zero of f(x) and x-3 is a factor of f(x).

If f(x) = x^3+3x^2+x+3,
And if f(-1) = 0,
Then -1 is a zero of f(x) and x+1 is a factor of f(x).

Answer 6

so x-3 works so would the answer be 5(x+3)(x^2+1)?

Answer 7

That is good, so long as it can't be factored further.

Answer 8

Thank you for helping :)