Question

trouble solving (x + 5)(x − 4)(x − 8) ≤ 0
I have found three solutions -5, 4 and 8, but what is the interval then? thanks.

Answer 1

cubic polynomial with positive leading coefficient looks like this

Answer 2

ok, so it would be something like (-inf, -5] U [-5,4] U [4,8] ?

Answer 3

the answer is given by the interval for which the curve satisfies <=0 condition.

So, the answer will be (-inf,-5] U [4,8]