-0.072*x^2+1.278*x-3.404=0

Solution for -0.072*x^2+1.278*x-3.404=0 equation:

-0.072x^2+1.278x-3.404=0

a = -0.072; b = 1.278; c = -3.404;
Δ = b2-4ac
Δ = 1.2782-4·(-0.072)·(-3.404)
Δ = 0.652932
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{-(1.278)-\sqrt{0.652932}}{2*-0.072}=\frac{-1.278-\sqrt{0.652932}}{-0.144}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.278)+\sqrt{0.652932}}{2*-0.072}=\frac{-1.278+\sqrt{0.652932}}{-0.144}
$