1.2(3x-16)(x+4)=0

Solution for 1.2(3x-16)(x+4)=0 equation:

1.2(3x-16)(x+4)=0

We multiply parentheses ..

1.2(+3x^2+12x-16x-64)=0

We multiply parentheses

3.6x^2+14.4x-19.2x-76.8=0

We add all the numbers together, and all the variables

3.6x^2-4.8x-76.8=0

a = 3.6; b = -4.8; c = -76.8;
Δ = b2-4ac
Δ = -4.82-4·3.6·(-76.8)
Δ = 1128.96
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4.8)-\sqrt{1128.96}}{2*3.6}=\frac{4.8-\sqrt{1128.96}}{7.2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.8)+\sqrt{1128.96}}{2*3.6}=\frac{4.8+\sqrt{1128.96}}{7.2}
$