How do you factor $8x^3 - 4y^2-50y+25$ ?

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Answer 1 · 2015-05-15T19:19:28

I think the question is probably incorrect in mixing $x$ and $y$ .

It looks like the intended problem was how to factor $8y^3-4y^2-50y+25$ , which you can do by grouping:

$8y^3-4y^2-50y+25$

$=(8y^3-4y^2)-(50y-25)$

$=4y^2(2y-1)-25(2y-1)$

$=(4y^2-25)(2y-1)$

The $4y^2-25$ factor can be factored further.

Notice that $4y^2-25 = (2y)^2-5^2$ , which is of the form $a^2-b^2$ .

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

So $4y^2-25 = (2y)^2-5^2 = (2y+5)(2y-5)$

So $8y^3-4y^2-50y+25 = (2y+5)(2y-5)(2y-1)$

How do you factor 8x^3 - 4y^2-50y+258x^3 - 4y^2-50y+25?