How do you factor $y=z^2 + 3z - 4$ ?

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Answer 1 · 2016-02-22T16:25:09

Factors of $z^2+3z−4$ are $(z-1)(z+4)$

To find the factors of $az^2+bz+c$ , one should find factors of $a*c$ whose sum is $b$ .

As the function is $z^2+3z−4$ , one should find factors of $1*(-4)$ or $-4$ whose sum is $3$ .

These are $-1$ and $4$ . Hence splitting middle term this way.

$z^2+3z−4$ = $z^2-1z+4z−4$ or

$z(z-1)+4(z-1)$ or $(z-1)(z+4)$

How do you factor y=z^2 + 3z - 4 y=z^2 + 3z - 4 ?