How do you simplify $(x - 5)(x+5)$ ?

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Answer 1 · 2018-04-19T21:52:57

$x^2-25$

This is an example of DOTS: the Difference Of Two Squares.

When we have two brackets where one is pos and one is neg with the same number, we can use this method:

DOTS allows us to cancel any x values, like so:

$(x-5)(x+5)$
$=x^2+5x-5x-25$

You can see here that due to the signs and the numbers being the same, the $+5x-5x$ cancel each other out to equal $0$ .

$=x^2-25$

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How do you simplify (x - 5)(x+5)(x - 5)(x+5)?