-0.8x^2+1.44x+9.72=0

Solution for -0.8x^2+1.44x+9.72=0 equation:

-0.8x^2+1.44x+9.72=0

a = -0.8; b = 1.44; c = +9.72;
Δ = b2-4ac
Δ = 1.442-4·(-0.8)·9.72
Δ = 33.1776
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{-(1.44)-\sqrt{33.1776}}{2*-0.8}=\frac{-1.44-\sqrt{33.1776}}{-1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.44)+\sqrt{33.1776}}{2*-0.8}=\frac{-1.44+\sqrt{33.1776}}{-1.6}
$