How do you factor $r^{2} - 25$ $r^2-25$ ?

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Answer 1 · 2015-06-04T06:56:51

$r^{2} - 25 = r^{2} - 5^{2} = (r - 5) (r + 5)$ $r^2-25 = r^2 - 5^2 = (r-5)(r+5)$

...using the difference of squares identity:

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

How do you factor r2−25r^2-25?