Thread: Binomial function

How would I factorize

x^3+2x^2-9x-18

and then solve

f(x)=0?

Thanks a lot.

Originally Posted by Yppolitia

How would I factorize

x^3+2x^2-9x-18

and then solve

f(x)=0?

Thanks a lot.

Factor by grouping: (Typically if you are asked to factor a cubic it will be a variation of this method.)






Now note that factors:

So we get:


So if we have

Then


So x = -3, -2, or 3.

-Dan

also if you do not know how to factor that well you could try and find one root, with the rational root theorem.

lets say that u have now since this has a root lets call it we then have


where . as you notice the degree of Q is one less than that of f.