H=6t^2-18t

Solution for H=6t^2-18t equation:

=6H^2-18H

We move all terms to the left:

-(6H^2-18H)=0

We get rid of parentheses

-6H^2+18H=0

a = -6; b = 18; c = 0;
Δ = b2-4ac
Δ = 182-4·(-6)·0
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-18}{2*-6}=\frac{-36}{-12}
=+3
$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+18}{2*-6}=\frac{0}{-12}
=0
$