-0.8x^2+10x+2=0

Solution for -0.8x^2+10x+2=0 equation:

-0.8x^2+10x+2=0

a = -0.8; b = 10; c = +2;
Δ = b2-4ac
Δ = 102-4·(-0.8)·2
Δ = 106.4
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{-(10)-\sqrt{106.4}}{2*-0.8}=\frac{-10-\sqrt{106.4}}{-1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+\sqrt{106.4}}{2*-0.8}=\frac{-10+\sqrt{106.4}}{-1.6}
$