h(h+5)=66

Solution for h(h+5)=66 equation:

h(h+5)=66

We move all terms to the left:

h(h+5)-(66)=0

We multiply parentheses

h^2+5h-66=0

a = 1; b = 5; c = -66;
Δ = b2-4ac
Δ = 52-4·1·(-66)
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-17}{2*1}=\frac{-22}{2}
=-11
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+17}{2*1}=\frac{12}{2}
=6
$