Question

What are roots of the equation -90=x (x-18)

Answer 1

-90=
`x`(
`x`-18)

-90=
`x^(2)`-18
`x`

`0=x^(2)-18x+90`

`x=9+3i or 9-3i`

Explanation:

you need to use quadratic formula and you will find square root a negative ( -9 ), which is an imaginary no.

square root (-9) = 3i