40x^2+336x+128=0

Solution for 40x^2+336x+128=0 equation:

40x^2+336x+128=0

a = 40; b = 336; c = +128;
Δ = b2-4ac
Δ = 3362-4·40·128
Δ = 92416
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{92416}=304$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(336)-304}{2*40}=\frac{-640}{80}
=-8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(336)+304}{2*40}=\frac{-32}{80}
=-2/5
$