7h(h-3)=14

Solution for 7h(h-3)=14 equation:

7h(h-3)=14

We move all terms to the left:

7h(h-3)-(14)=0

We multiply parentheses

7h^2-21h-14=0

a = 7; b = -21; c = -14;
Δ = b2-4ac
Δ = -212-4·7·(-14)
Δ = 833
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:

$\sqrt{\Delta}=\sqrt{833}=\sqrt{49*17}=\sqrt{49}*\sqrt{17}=7\sqrt{17}$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-7\sqrt{17}}{2*7}=\frac{21-7\sqrt{17}}{14}
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+7\sqrt{17}}{2*7}=\frac{21+7\sqrt{17}}{14}
$