Can someone help me? I need to factor completely the following <span title="problem:cx^2-cy^2-dx^2+dy^2?">problem:cx^2-cy^2-dx^2+dy...</span>

Question

I'm taking a college algebra class and my professor calls this a review. I feel so hopeless if I don't even get the review. I just need a little help. Thank you so much for your time...

Answer 1

cx² - cy² - dx² + dy² = c(x² - y²) + d(-x² + y²)

= c(x² - y²) - d(x² - y²)

= (c-d)(x² - y²)

= (c-d)(x+y)(x-y)

That last factoring comes from the &quot;difference of squares&quot; rule

a² - b² = (a+b)(a-b)