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

##### 1 Answer

Oct 24, 2015

Separate out the common factor

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

#### Explanation:

Both

#-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)#