How do you factor $3x^3 + 27x^2y – 24xy – 216y^2$ ?

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Answer 1 · 2016-03-28T22:13:18

$3x^3+27x^2y-24xy-216y^2=3(x^2-8y)(x+9y)$

Separate out common scalar factor $3$ , then factor by grouping:

$3x^3+27x^2y-24xy-216y^2$

$=3(x^3+9x^2y-8xy-72y^2)$

$=3((x^3+9x^2y)-(8xy+72y^2))$

$=3(x^2(x+9y)-8y(x+9y))$

$=3(x^2-8y)(x+9y)$

How do you factor 3x^3 + 27x^2y – 24xy – 216y^23x^3 + 27x^2y – 24xy – 216y^2?