2x(x+1.2)=56

Solution for 2x(x+1.2)=56 equation:

2x(x+1.2)=56

We move all terms to the left:

2x(x+1.2)-(56)=0

We multiply parentheses

2x^2+2.4x-56=0

a = 2; b = 2.4; c = -56;
Δ = b2-4ac
Δ = 2.42-4·2·(-56)
Δ = 453.76
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{-(2.4)-\sqrt{453.76}}{2*2}=\frac{-2.4-\sqrt{453.76}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.4)+\sqrt{453.76}}{2*2}=\frac{-2.4+\sqrt{453.76}}{4}
$