How do you factor $y=3x^3-300x$ ?

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Answer 1 · 2015-12-18T14:22:12

$y = 3x(x^2 - 100)$

There is at least one $x$ on every term at the right so you can already factorize by $x$ , which gives you $y = x(3x^2 + 300)$ .

But 300 and 3 both have 3 as common divisor, so you can also say that $y = 3x(x^2 - 100)$ . I hope that answers your question.

Answer 2 · 2015-12-18T16:18:39

$y=3x(x-10)(x+10)$

Factoring out $3x$ gives:

$y=3x(x^2-100)$

But $100$ is $10^2$ giving:

$y=3x(x^2-10^2)$

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

Applying this to our question gives:

$y=3x(x-10)(x+10)$

How do you factor y=3x^3-300x y=3x^3-300x ?