3x(2.4x-1.6)+3=2.8

Solution for 3x(2.4x-1.6)+3=2.8 equation:

3x(2.4x-1.6)+3=2.8

We move all terms to the left:

3x(2.4x-1.6)+3-(2.8)=0

We add all the numbers together, and all the variables

3x(2.4x-1.6)+0.2=0

We multiply parentheses

6x^2-4.8x+0.2=0

a = 6; b = -4.8; c = +0.2;
Δ = b2-4ac
Δ = -4.82-4·6·0.2
Δ = 18.24
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{18.24}}{2*6}=\frac{4.8-\sqrt{18.24}}{12}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.8)+\sqrt{18.24}}{2*6}=\frac{4.8+\sqrt{18.24}}{12}
$