(x+5)(16-3x)=0

Solution for (x+5)(16-3x)=0 equation:

(x+5)(16-3x)=0

We add all the numbers together, and all the variables

(x+5)(-3x+16)=0

We multiply parentheses ..

(-3x^2+16x-15x+80)=0

We get rid of parentheses

-3x^2+16x-15x+80=0

We add all the numbers together, and all the variables

-3x^2+x+80=0

a = -3; b = 1; c = +80;
Δ = b2-4ac
Δ = 12-4·(-3)·80
Δ = 961
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{961}=31$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-31}{2*-3}=\frac{-32}{-6}
=5+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+31}{2*-3}=\frac{30}{-6}
=-5
$