-4.9t^2+12.25t+115=0

Solution for -4.9t^2+12.25t+115=0 equation:

-4.9t^2+12.25t+115=0

a = -4.9; b = 12.25; c = +115;
Δ = b2-4ac
Δ = 12.252-4·(-4.9)·115
Δ = 2404.0625
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{-(12.25)-\sqrt{2404.0625}}{2*-4.9}=\frac{-12.25-\sqrt{2404.0625}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12.25)+\sqrt{2404.0625}}{2*-4.9}=\frac{-12.25+\sqrt{2404.0625}}{-9.8}
$