4.9t^2-4.9t-29.4=0

Solution for 4.9t^2-4.9t-29.4=0 equation:

4.9t^2-4.9t-29.4=0

a = 4.9; b = -4.9; c = -29.4;
Δ = b2-4ac
Δ = -4.92-4·4.9·(-29.4)
Δ = 600.25
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{-(-4.9)-\sqrt{600.25}}{2*4.9}=\frac{4.9-\sqrt{600.25}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.9)+\sqrt{600.25}}{2*4.9}=\frac{4.9+\sqrt{600.25}}{9.8}
$