0.02y^2+4y-90000=0

Solution for 0.02y^2+4y-90000=0 equation:

0.02y^2+4y-90000=0

a = 0.02; b = 4; c = -90000;
Δ = b2-4ac
Δ = 42-4·0.02·(-90000)
Δ = 7216
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{7216}=\sqrt{16*451}=\sqrt{16}*\sqrt{451}=4\sqrt{451}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-4\sqrt{451}}{2*0.02}=\frac{-4-4\sqrt{451}}{0.04}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+4\sqrt{451}}{2*0.02}=\frac{-4+4\sqrt{451}}{0.04}
$