H=-2t2+9t+1

Solution for H=-2t2+9t+1 equation:

=-2H^2+9H+1

We move all terms to the left:

-(-2H^2+9H+1)=0

We get rid of parentheses

2H^2-9H-1=0

a = 2; b = -9; c = -1;
Δ = b2-4ac
Δ = -92-4·2·(-1)
Δ = 89
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{-(-9)-\sqrt{89}}{2*2}=\frac{9-\sqrt{89}}{4}
$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+\sqrt{89}}{2*2}=\frac{9+\sqrt{89}}{4}
$