10h2+9=21h

Solution for 10h2+9=21h equation:

10h^2+9=21h

We move all terms to the left:

10h^2+9-(21h)=0

a = 10; b = -21; c = +9;
Δ = b2-4ac
Δ = -212-4·10·9
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-9}{2*10}=\frac{12}{20}
=3/5
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+9}{2*10}=\frac{30}{20}
=1+1/2
$