10h(h+1)-4=76

Solution for 10h(h+1)-4=76 equation:

10h(h+1)-4=76

We move all terms to the left:

10h(h+1)-4-(76)=0

We add all the numbers together, and all the variables

10h(h+1)-80=0

We multiply parentheses

10h^2+10h-80=0

a = 10; b = 10; c = -80;
Δ = b2-4ac
Δ = 102-4·10·(-80)
Δ = 3300
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3300}=\sqrt{100*33}=\sqrt{100}*\sqrt{33}=10\sqrt{33}$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-10\sqrt{33}}{2*10}=\frac{-10-10\sqrt{33}}{20}
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+10\sqrt{33}}{2*10}=\frac{-10+10\sqrt{33}}{20}
$