How do you factor $7x^2-847$ ?

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Answer 1 · 2017-02-17T11:40:54

You first try to divide $847div7=121$

So we now have
$=7*(x^2-121)$

Notice that $121=11^2$ and you get the special product for the difference of two squares: $a^2-b^2=(a+b)(a-b)$ :

$=7(x+11)(x-11)$

How do you factor 7x^2-8477x^2-847?