What are the intervals?

Question

y = 8x^2 − 88x + 240
There are two intervals
working out would be helpful thanks

Answer 1

8x^2 -88x+240 = x^2 - 11x +30
= (x-5)(x-6)
hence x1=5 and x2=6

if 0<8x^2-88x+240, then 5>x or 6 else is5

Answer 2

I assume you mean intervals where y > 0, or something like that.

y = 8x^2 - 88x + 240
= 8(x^2 - 11x + 30)
= 8(x-5)(x-6)

So y is positive when x-5 < 0 and x-6 < 0, or when x-5 > 0 and x-6 > 0.
i.e. when x < 5 and x < 6, or when x > 5 and x > 6
i.e. when x < 5 or when x > 6.
So the intervals for which y > 0 are (-∞, -5) and (6, ∞).