5x(-x+20)=16

Solution for 5x(-x+20)=16 equation:

5x(-x+20)=16

We move all terms to the left:

5x(-x+20)-(16)=0

We add all the numbers together, and all the variables

5x(-1x+20)-16=0

We multiply parentheses

-5x^2+100x-16=0

a = -5; b = 100; c = -16;
Δ = b2-4ac
Δ = 1002-4·(-5)·(-16)
Δ = 9680
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{9680}=\sqrt{1936*5}=\sqrt{1936}*\sqrt{5}=44\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-44\sqrt{5}}{2*-5}=\frac{-100-44\sqrt{5}}{-10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+44\sqrt{5}}{2*-5}=\frac{-100+44\sqrt{5}}{-10}
$