Question

what are the zeros of the polynomial function: f(x)=x^3-2x^2-8x

Answer 1

Well you can start by factoring out an x

\[\large x(x^2 - 2x - 8)\]
Now factor the inside...

wat numbers multiply to become -8 but ALSO add to be -2?

Answer 2

The factors of 8..hmm lets see...

8 times 1 works
4 times 2 works....hey this looks about right

So lets try 4 and 2

\[\large x((x - 4)(x + 2))\]

There we go...now what values of 'x' can we plug into this equation to make the whole thing = 0?

Hint....anything times 0 = 0 and this whole function is multiplying