-0.8x^2+8x=19.2

Solution for -0.8x^2+8x=19.2 equation:

-0.8x^2+8x=19.2

We move all terms to the left:

-0.8x^2+8x-(19.2)=0

We add all the numbers together, and all the variables

-0.8x^2+8x-19.2=0

a = -0.8; b = 8; c = -19.2;
Δ = b2-4ac
Δ = 82-4·(-0.8)·(-19.2)
Δ = 2.56
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{-(8)-\sqrt{2.56}}{2*-0.8}=\frac{-8-\sqrt{2.56}}{-1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+\sqrt{2.56}}{2*-0.8}=\frac{-8+\sqrt{2.56}}{-1.6}
$