(x-3)*(16-4x)=0

Solution for (x-3)*(16-4x)=0 equation:

(x-3)(16-4x)=0

We add all the numbers together, and all the variables

(x-3)(-4x+16)=0

We multiply parentheses ..

(-4x^2+16x+12x-48)=0

We get rid of parentheses

-4x^2+16x+12x-48=0

We add all the numbers together, and all the variables

-4x^2+28x-48=0

a = -4; b = 28; c = -48;
Δ = b2-4ac
Δ = 282-4·(-4)·(-48)
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-4}{2*-4}=\frac{-32}{-8}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+4}{2*-4}=\frac{-24}{-8}
=+3
$