-20=-45h^2-80h

Solution for -20=-45h^2-80h equation:

-20=-45h^2-80h

We move all terms to the left:

-20-(-45h^2-80h)=0

We get rid of parentheses

45h^2+80h-20=0

a = 45; b = 80; c = -20;
Δ = b2-4ac
Δ = 802-4·45·(-20)
Δ = 10000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{10000}=100$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-100}{2*45}=\frac{-180}{90}
=-2
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+100}{2*45}=\frac{20}{90}
=2/9
$