# How do you use the rational roots theorem to find all possible zeros of #P(x)= x^3 + 3x^2 - 4#?

##### 1 Answer

Aug 9, 2016

#### Explanation:

#P(x) = x^3+3x^2-4#

By the rational root theorem, any *rational* zeros of

That means that the only possible *rational* zeros are:

#+-1, +-2, +-4#

We find:

#P(1) = 1+3-4 = 0#

So

#x^3+3x^2-4=(x-1)(x^2+4x+4)#

The remaining quadratic is a perfect square trinomial:

#x^2+4x+4 = (x+2)^2#

Hence the remaining zero is