Y=-16x2+72x

Solution for Y=-16x2+72x equation:

=-16Y^2+72Y

We move all terms to the left:

-(-16Y^2+72Y)=0

We get rid of parentheses

16Y^2-72Y=0

a = 16; b = -72; c = 0;
Δ = b2-4ac
Δ = -722-4·16·0
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-72)-72}{2*16}=\frac{0}{32}
=0
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-72)+72}{2*16}=\frac{144}{32}
=4+1/2
$