4.9t^2+15t-80=0

Solution for 4.9t^2+15t-80=0 equation:

4.9t^2+15t-80=0

a = 4.9; b = 15; c = -80;
Δ = b2-4ac
Δ = 152-4·4.9·(-80)
Δ = 1793
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{-(15)-\sqrt{1793}}{2*4.9}=\frac{-15-\sqrt{1793}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{1793}}{2*4.9}=\frac{-15+\sqrt{1793}}{9.8}
$