Example:
x^2+2x-3
If we factor it, we can get
(x-1)(x+3)
Use the distributive property to check that we factored it right:
x^2-x+3x-3
Simplify
x^2+2x-3
Therefore the distributive property can be used to ensure that you've factored your trinomial correctly. If you have, you should get the same trinomial you started with.
