-0.64x^2+2x+120=0

Solution for -0.64x^2+2x+120=0 equation:

-0.64x^2+2x+120=0

a = -0.64; b = 2; c = +120;
Δ = b2-4ac
Δ = 22-4·(-0.64)·120
Δ = 311.2
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)-\sqrt{311.2}}{2*-0.64}=\frac{-2-\sqrt{311.2}}{-1.28}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+\sqrt{311.2}}{2*-0.64}=\frac{-2+\sqrt{311.2}}{-1.28}
$