Question

How do you completely factor `x^3+9x^2+12x+15` given x+5 is one of the factors?

Answer 1

Let, `p(x)=x^3+9x^2+12x+15`, and, we are given that `(x+5)`

is a factor of `p(x)`.

But, this is not true , because,

`p(-5)=-125+225-60+15=55!=0`

Explanation:

Let, `p(x)=x^3+9x^2+12x+15`, and, we are given that `(x+5)`

is a factor of `p(x)`.

But, this is not true , because,

`p(-5)=-125+225-60+15=55!=0`