30=4h^2+10h

Solution for 30=4h^2+10h equation:

30=4h^2+10h

We move all terms to the left:

30-(4h^2+10h)=0

We get rid of parentheses

-4h^2-10h+30=0

a = -4; b = -10; c = +30;
Δ = b2-4ac
Δ = -102-4·(-4)·30
Δ = 580
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:

$\sqrt{\Delta}=\sqrt{580}=\sqrt{4*145}=\sqrt{4}*\sqrt{145}=2\sqrt{145}$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-2\sqrt{145}}{2*-4}=\frac{10-2\sqrt{145}}{-8}
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+2\sqrt{145}}{2*-4}=\frac{10+2\sqrt{145}}{-8}
$