72x-2x^2=A

Solution for 72x-2x^2=A equation:

72x-2x^2=

We move all terms to the left:

72x-2x^2-()=0

We add all the numbers together, and all the variables

-2x^2+72x=0

a = -2; b = 72; c = 0;
Δ = b2-4ac
Δ = 722-4·(-2)·0
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(72)-72}{2*-2}=\frac{-144}{-4}
=+36
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(72)+72}{2*-2}=\frac{0}{-4}
=0
$