Question

How do you solve `x^2 - 3x - 10 = 0`?

Answer 1

`x^2-3x-10 = (x-5)(x+2)`

So `x^2-3x-10=0` has roots `x=5` and `x=-2`.

Explanation:

If `x^2-3x-10 = (x-a)(x+b) = x^2-(a-b)x-ab`

then `a*b = 10` and `a-b=3`.

That is satisfied by `a=5` and `b=2`.