16x(5-x)=64

Solution for 16x(5-x)=64 equation:

16x(5-x)=64

We move all terms to the left:

16x(5-x)-(64)=0

We add all the numbers together, and all the variables

16x(-1x+5)-64=0

We multiply parentheses

-16x^2+80x-64=0

a = -16; b = 80; c = -64;
Δ = b2-4ac
Δ = 802-4·(-16)·(-64)
Δ = 2304
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2304}=48$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-48}{2*-16}=\frac{-128}{-32}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+48}{2*-16}=\frac{-32}{-32}
=1
$