-4.9t^2+24.5t+120=0

Solution for -4.9t^2+24.5t+120=0 equation:

-4.9t^2+24.5t+120=0

a = -4.9; b = 24.5; c = +120;
Δ = b2-4ac
Δ = 24.52-4·(-4.9)·120
Δ = 2952.25
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{-(24.5)-\sqrt{2952.25}}{2*-4.9}=\frac{-24.5-\sqrt{2952.25}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(24.5)+\sqrt{2952.25}}{2*-4.9}=\frac{-24.5+\sqrt{2952.25}}{-9.8}
$