How do you factor completely ab^2 - 3b^2 - 4a + 12ab23b24a+12?

1 Answer
Jan 6, 2016

=color(green)((b^2-4)(a-3)=(b24)(a3)

Explanation:

ab^2 -3b^2-4a +12ab23b24a+12

We can make groups of two to factorise this expression:
(ab^2 -3b^2) + (-4a +12)(ab23b2)+(4a+12)

b^2b2 is common to both the terms in the first group, and -44 is common to both the terms in the second group.
We can write the expression as :
b^2(a -3) -4 (a -3)b2(a3)4(a3)

Now, The term (a-3)(a3) is common to both the terms
=color(green)((b^2-4)(a-3)=(b24)(a3)