How do you factor $25x^2-9$ ?

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Answer 1 · 2015-07-26T15:21:26

You write the expression as a difference of two perfect squares.

You can factor your expression by writing it as a difference of two perfect squares, for which you know that

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

In your case, you can write

$25x^2 - 9 = 5x * 5x - 3 * 3$ , which is equivalent to

$(5x)^2 - 3^2 = color(green)((5x-3)(5x+3))$

How do you factor 25x^2-925x^2-9?