Question

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

Answer 1

You first try to divide `847div7=121`

Explanation:

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)`