Question 383501
problem is:


(a^2 - b^2)/(a-b)


(a^2 - b^2) can be factored to be (a-b) * (a+b)


your expression becomes:


((a-b) * (a+b)) / (a-b)


The (a-b) in the numerator and denominator cancel out and you are left with:


1 * (a+b) / 1 = (a+b)


you had to know that (a^2 - b^2) is equivalent to (a+b) * (a-b).


when you take (a+b) and multiply it by (a-b), you get:


a^2 + ab - ab - b^2 which becomes a^2 - b^2 because the +ab and -ab cancel out.