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

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Answer 1 · 2015-10-24T21:47:22

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

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

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

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

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