How do you factor $y^2-49$ ?

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Answer 1 · 2015-07-26T15:50:56

Rewrite the expression as a difference of two perfect squares.

You can factor the difference of two perfect squares by using the formula

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

You already have one perfect square, $y^2$ , now all you have to do is write $49$ as a perfect square, too.

$49 = 7 * 7 = 7^2$

The original expression now becomes

$y^2 - 7^2 = color(green)((y+7)(y-7))$

How do you factor y^2-49y^2-49?