What is y = x^2 + 2x - 8 factored?

Question

how to factor when there is 2 variables

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Answer 1 · 2018-05-02T21:38:19

$x^2+2x-8=0$

$x=(-2+-sqrt(2^2-4*1*(-8)))/(2*1)=(-2+-sqrt(36))/(2)=(-2+-6)/(2)$

$x=(-2-6)/(2)=(-8)/(2)=-4$

$x=(-2+6)/(2)=(4)/(2)=2$

$y=(x+4)(x-2)$

If you want to factorize $x^2+2x-8$ .

Choosing the quadratic equation to factorize.

$x^2+2x-8=0$

$x=(-b+-sqrt(b^2-4ac))/(2a)$

Where $a=1, b=2$ and $c=-8$

$x=(-2+-sqrt(2^2-4*1*(-8)))/(2*1)=(-2+-sqrt(36))/(2)=(-2+-6)/(2)$

Which will give,
$x=(-2-6)/(2)=(-8)/(2)=-4$
And,
$x=(-2+6)/(2)=(4)/(2)=2$

Your factorized form will then be,

$(x+4)(x-2)$