How do you factor #28u ^ { 4} - 63u ^ { 2}#?

1 Answer
Sep 2, 2017

#7u^2(2u-3)(2u+3)#

Explanation:

First we look for common factors between the terms. You should notice the coefficients both divide by 7.

#7(4u^4-9u^2)#

Both terms also have #u^2# in common, so we can pull that out front as well.

#7u^2(4u^2-9)#

#4u^2-9# is a difference of squares, so we can factor it too.

#7u^2(2u-3)(2u+3)#