H(t)=-4t^2+12t+72

Solution for H(t)=-4t^2+12t+72 equation:

(H)=-4H^2+12H+72

We move all terms to the left:

(H)-(-4H^2+12H+72)=0

We get rid of parentheses

4H^2-12H+H-72=0

We add all the numbers together, and all the variables

4H^2-11H-72=0

a = 4; b = -11; c = -72;
Δ = b2-4ac
Δ = -112-4·4·(-72)
Δ = 1273
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-11)-\sqrt{1273}}{2*4}=\frac{11-\sqrt{1273}}{8}
$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+\sqrt{1273}}{2*4}=\frac{11+\sqrt{1273}}{8}
$