Question

How do you solve `-15x^2 + 18x = 0`?

Answer 1

First factor: `0 = -15 x^2 + 18 x = -3 x(5x - 6)` so `x=0` or `5x-6=0`, that is, `x=6/5.`

Explanation:

Check:

`-15(0)^2 + 18(0) = 0 quad sqrt`

`-15(6/5)^2 + 18(6/5)`

`= -15(36/25) + {3(36)}/5`

`= -{3(36)}/5 + {3(36)}/5 = 0 quad sqrt`