H=72-0.05x2

Solution for H=72-0.05x2 equation:

=72-0.05H^2

We move all terms to the left:

-(72-0.05H^2)=0

We get rid of parentheses

0.05H^2-72=0

a = 0.05; b = 0; c = -72;
Δ = b2-4ac
Δ = 02-4·0.05·(-72)
Δ = 14.4
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{-(0)-\sqrt{14.4}}{2*0.05}=\frac{0-\sqrt{14.4}}{0.1}
=-\frac{\sqrt{}}{0.1}
$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{14.4}}{2*0.05}=\frac{0+\sqrt{14.4}}{0.1}
=\frac{\sqrt{}}{0.1}
$