H=-16t^2+66t+4

Solution for H=-16t^2+66t+4 equation:

=-16H^2+66H+4

We move all terms to the left:

-(-16H^2+66H+4)=0

We get rid of parentheses

16H^2-66H-4=0

a = 16; b = -66; c = -4;
Δ = b2-4ac
Δ = -662-4·16·(-4)
Δ = 4612
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{4612}=\sqrt{4*1153}=\sqrt{4}*\sqrt{1153}=2\sqrt{1153}$
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-66)-2\sqrt{1153}}{2*16}=\frac{66-2\sqrt{1153}}{32}
$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-66)+2\sqrt{1153}}{2*16}=\frac{66+2\sqrt{1153}}{32}
$