How we can check the answer when we factor?

Question

How we can check the answer when we factor?

Answer 1

Michael's answer is correct, but here is an example to show you how to do it!

 

Say you are asked to factor the following equation:

 

x^2 - x - 12

 

Of course, in order to factor it, you have to find two numbers that have a difference of -1 and when multiplied are equal to -12. One of the numbers has to be negative so that the 12 is negative. In this case, the numbers are 3 and 4.

 

So, your factoring should look like this:

 

(x+3)(x-4)

 

Now, in order to make sure that this is the correct answer, use FOIL to multiply these factors out and you should get the polynomial you were asked to factor!

 

x^2 + 3x - 4x -12

x^2 - x - 12

 

Answer 2

Suppose you are factoring a polynomial using FOIL or taking out the GCF.  You will end up with two factor polynomials.

 

 

If you multiply the factor polynomials, you should end up the with the polynomial you started with.