4.9t^2-60t-200=0

Solution for 4.9t^2-60t-200=0 equation:

4.9t^2-60t-200=0

a = 4.9; b = -60; c = -200;
Δ = b2-4ac
Δ = -602-4·4.9·(-200)
Δ = 7520
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{7520}=\sqrt{16*470}=\sqrt{16}*\sqrt{470}=4\sqrt{470}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-4\sqrt{470}}{2*4.9}=\frac{60-4\sqrt{470}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+4\sqrt{470}}{2*4.9}=\frac{60+4\sqrt{470}}{9.8}
$