How do you factor #-7x^4 + 567x^2#?

1 Answer
Oct 24, 2015

Answer:

Separate out the common factor #-7x^2# then use the difference of squares identity to find:

#-7x^4+567x^2 = -7x^2(x-9)(x+9)#

Explanation:

Both #-7x^4# and #567x^2# are divisible by #-7x^2#, so separate it out as a factor to find:

#-7x^4+567x^2 = -7x^2(x^2-81) = -7x^2(x^2-9^2) = -7x^2(x-9)(x+9)#

...using the difference of squares identity

#a^2-b^2 = (a-b)(a+b)#