-4x(5x-8)=-48

Solution for -4x(5x-8)=-48 equation:

-4x(5x-8)=-48

We move all terms to the left:

-4x(5x-8)-(-48)=0

We add all the numbers together, and all the variables

-4x(5x-8)+48=0

We multiply parentheses

-20x^2+32x+48=0

a = -20; b = 32; c = +48;
Δ = b2-4ac
Δ = 322-4·(-20)·48
Δ = 4864
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:

$\sqrt{\Delta}=\sqrt{4864}=\sqrt{256*19}=\sqrt{256}*\sqrt{19}=16\sqrt{19}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(32)-16\sqrt{19}}{2*-20}=\frac{-32-16\sqrt{19}}{-40}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(32)+16\sqrt{19}}{2*-20}=\frac{-32+16\sqrt{19}}{-40}
$