-0.8x^2+3x+1.5=0

Solution for -0.8x^2+3x+1.5=0 equation:

-0.8x^2+3x+1.5=0

a = -0.8; b = 3; c = +1.5;
Δ = b2-4ac
Δ = 32-4·(-0.8)·1.5
Δ = 13.8
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{-(3)-\sqrt{13.8}}{2*-0.8}=\frac{-3-\sqrt{13.8}}{-1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{13.8}}{2*-0.8}=\frac{-3+\sqrt{13.8}}{-1.6}
$