Question

How do you solve `-x^2 + 100x - 2400 >= 0`?

Answer 1

`40 le x le 60`

Explanation:

`-x^2+100x-2400 ge 0`
`implies -(x^2 -100x +2400) ge 0`
`implies x^2 -100x +2400 le 0`
`implies x^2 -100x +2500 le 100`
`implies (x -50)^2 le 10^2`
`implies -10 le x-50 le 10`
`implies 40 le x le 60`