Hi all, this is really bothering me... I am just not seeing how ...
(x-a)+(x-a)(x+a) ----> (x-a)(x+a+a)
..... I know this is true because I have looked it up in a solution manual and my professor did this on the board. How!!!? Any help would be greatly apprieciated!
(x-a)+(x-a)(x+a) ----> (x-a)(x+a+a) . this is not always true, are you sure it's not a typo? put a = 3 for example and expand the left hand side, you get a different answer from when you expand the right hand side with a = 3.
the way i see to do this is to factor the common (x - a) out
(x-a)+(x-a)(x+a) = (x - a)(1 + (x + a)) = (x - a)(x + a + 1)