# How do I use zero factor property in reverse?

##### 1 Answer

You use it to determine the polynomial function.

We can use it for higher degree polynomials, but let's use a cubic as an example. Suppose we have the zeros: -3, 2.5, and 4. So:

#x=-3#

#x+3=0#

#x=2.5#

#x=5/2#

#2x=5# multiply both sides by denominator

#2x-5=0#

#x=4#

#x-4=0#

So, the polynomial function is

#P(x)=2x^3-7x^2-19x+60#

The common mistake in this problem is the sign of the roots. So make sure you do the individuals steps to avoid this mistake.