40t-4.9t^2=50

Solution for 40t-4.9t^2=50 equation:

40t-4.9t^2=50

We move all terms to the left:

40t-4.9t^2-(50)=0

a = -4.9; b = 40; c = -50;
Δ = b2-4ac
Δ = 402-4·(-4.9)·(-50)
Δ = 620
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-\sqrt{620}}{2*-4.9}=\frac{-40-\sqrt{620}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+\sqrt{620}}{2*-4.9}=\frac{-40+\sqrt{620}}{-9.8}
$