if a number is added to its square, it equals 20

if a number is added to its square, it equals 20.

Let the number be an arbitrary variable, let's call it n.
The square of the number means we raise n to the power of 2:
n^2

We add n^2 to n:
n^2 + n

It equals 20 so we set n^2 + n equal to 20
n^2 + n = 20

This is a quadratic equation. So we type this equation into our search engine to solve for n and we get two solutions:
n = (-5, 4)