Question

What are the zeros of the function `f(x) = x^2-13x-30`?

Answer 1

`15` and `-2`

Explanation:

Find a pair of factors of `30` with difference `13`.

The pair `15, 2` works in that `15*2 = 30` and `15-2=13`

Hence we find:

`x^2-13x-30 = (x-15)(x+2)`

So the zeros of `f(x)` are the zeros of `(x-15)` and `(x+2)`, namely `15` and `-2`