6h(h-3)=18

Solution for 6h(h-3)=18 equation:

6h(h-3)=18

We move all terms to the left:

6h(h-3)-(18)=0

We multiply parentheses

6h^2-18h-18=0

a = 6; b = -18; c = -18;
Δ = b2-4ac
Δ = -182-4·6·(-18)
Δ = 756
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:

$\sqrt{\Delta}=\sqrt{756}=\sqrt{36*21}=\sqrt{36}*\sqrt{21}=6\sqrt{21}$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-6\sqrt{21}}{2*6}=\frac{18-6\sqrt{21}}{12}
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+6\sqrt{21}}{2*6}=\frac{18+6\sqrt{21}}{12}
$