91=(2h-1)*h

Solution for 91=(2h-1)*h equation:

91=(2h-1)*h

We move all terms to the left:

91-((2h-1)*h)=0


We calculate terms in parentheses: -((2h-1)*h), so:

(2h-1)*h

We multiply parentheses

2h^2-1h

Back to the equation:

-(2h^2-1h)


We get rid of parentheses

-2h^2+1h+91=0

We add all the numbers together, and all the variables

-2h^2+h+91=0

a = -2; b = 1; c = +91;
Δ = b2-4ac
Δ = 12-4·(-2)·91
Δ = 729
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{729}=27$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-27}{2*-2}=\frac{-28}{-4}
=+7
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+27}{2*-2}=\frac{26}{-4}
=-6+1/2
$