How do you factor $25z^4 - 5z^2 - 12$ ?

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Answer 1 · 2015-12-23T11:31:58

Use substitution

Substitute $x= 5z^2$ to simplify the expression to become
$x^2 - x -12$
$=(x-4)(x+3)$
Substituting back gives
$(5z^2 - 4)(5z^2+3)$

How do you factor 25z^4 - 5z^2 - 1225z^4 - 5z^2 - 12?