0.005t^2+4t-1000=0

Solution for 0.005t^2+4t-1000=0 equation:

0.005t^2+4t-1000=0

a = 0.005; b = 4; c = -1000;
Δ = b2-4ac
Δ = 42-4·0.005·(-1000)
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-6}{2*0.005}=\frac{-10}{0.01}
=-1000
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+6}{2*0.005}=\frac{2}{0.01}
=200
$