How do you multiply $(x - 7) (x + 7)$ ?

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Answer 1 · 2015-07-13T17:43:44

$=color(blue)(x^2-49$

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

The same property can be applied to the expression $(x-7)(x+7)$ where $color(blue)(a)=x, color(blue)(b)=7$

So,
$(x-7)(x+7) = x^2-7^2$

$=color(blue)(x^2-49$

How do you multiply (x - 7) (x + 7)(x - 7) (x + 7)?