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

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

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

We add all the numbers together, and all the variables

(-1x+4)(4x+3)=0

We multiply parentheses ..

(-4x^2-3x+16x+12)=0

We get rid of parentheses

-4x^2-3x+16x+12=0

We add all the numbers together, and all the variables

-4x^2+13x+12=0

a = -4; b = 13; c = +12;
Δ = b2-4ac
Δ = 132-4·(-4)·12
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-19}{2*-4}=\frac{-32}{-8}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+19}{2*-4}=\frac{6}{-8}
=-3/4
$