H=-11t^2+66t

Solution for H=-11t^2+66t equation:

=-11H^2+66H

We move all terms to the left:

-(-11H^2+66H)=0

We get rid of parentheses

11H^2-66H=0

a = 11; b = -66; c = 0;
Δ = b2-4ac
Δ = -662-4·11·0
Δ = 4356
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4356}=66$
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-66)-66}{2*11}=\frac{0}{22}
=0
$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-66)+66}{2*11}=\frac{132}{22}
=6
$