How do you factor $42x^2 + 5xy - 25y^2$ ?

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Answer 1 · 2018-04-08T01:42:51

$(6x-5)(7x+5)$

$(6x-5)(7x+5)$

You can use the quadratic formula or the cross-multiply rule (i think that's what it's called)

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

$a=42,b=5,c=-25$

$x=(-5+-sqrt(5^2-4*42*-25))/(2*42)$

$x=(-5+-sqrt(4225))/84$

$x=(-5+-65)/84$

$x=-70/84=-5/6$ or $x=60/84=5/7$

So your equation is

$(x-5/6)(x+5/7)$

= $(6x-5)(7x+5)$

How do you factor 42x^2 + 5xy - 25y^242x^2 + 5xy - 25y^2?