Thread: factor expression

(a²+2a)²-2(a²+2a)-3

u=(a²+2a)

(u)²-2u-3

(u+1)(u-3)

(a²+2a+1)(a²+2a-3)

WORNG ANS (a+1)(a+1)(a-1)(a+3)

I can't see why this is wrong ((a+1)(a+1)(a-1)(a+3))... ...
What is the correct ans?

Originally Posted by zbest1966

WORNG ANS (a+1)(a+1)(a-1)(a+3)

I agree with Goku, this looks correct.

The only other thing you could maybe do is combine the two factors of :

correct (a+2)(a-2)(a+1)(a-1)

Originally Posted by zbest1966

correct (a+2)(a-2)(a+1)(a-1)

No, that is incorrect. You can verify this by substituting values for .

Your original answer was the right one.

Originally Posted by zbest1966

(a²+2a)²-2(a²+2a)-3

u=(a²+2a)

(u)²-2u-3

(u+1)(u-3)

(a²+2a+1)(a²+2a-3)

You're on the right track. Now all you need to do is factor those two expresions.

(a²+2a+1) = (a+1)(a+1)
(a²+2a-3) = (a+3)(a-1)