Question

A certain number added to its square is equal to 90. What is/are the number(s) that work?

Answer 1

9,-10 the guy above got what I got

Answer 2

9,-10

Explanation:

Let u be a number.

`u + {u}^(2) = 90`

`u {}^(2) + u - 90 = 0`

`(u + 10)(u - 9) = 0`

`u = - 10`

or

`u = 9`

9, -10