y^2-0.9405y-1.685=0

Solution for y^2-0.9405y-1.685=0 equation:

y^2-0.9405y-1.685=0

a = 1; b = -0.9405; c = -1.685;
Δ = b2-4ac
Δ = -0.94052-4·1·(-1.685)
Δ = 7.62454025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.9405)-\sqrt{7.62454025}}{2*1}=\frac{0.9405-\sqrt{7.62454025}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.9405)+\sqrt{7.62454025}}{2*1}=\frac{0.9405+\sqrt{7.62454025}}{2}
$