(2h-9)(2h-9)=9

Solution for (2h-9)(2h-9)=9 equation:

(2h-9)(2h-9)=9

We move all terms to the left:

(2h-9)(2h-9)-(9)=0

We multiply parentheses ..

(+4h^2-18h-18h+81)-9=0

We get rid of parentheses

4h^2-18h-18h+81-9=0

We add all the numbers together, and all the variables

4h^2-36h+72=0

a = 4; b = -36; c = +72;
Δ = b2-4ac
Δ = -362-4·4·72
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-12}{2*4}=\frac{24}{8}
=3
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+12}{2*4}=\frac{48}{8}
=6
$