-4.9t^2+14t+2.1=0

Solution for -4.9t^2+14t+2.1=0 equation:

-4.9t^2+14t+2.1=0

a = -4.9; b = 14; c = +2.1;
Δ = b2-4ac
Δ = 142-4·(-4.9)·2.1
Δ = 237.16
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{-(14)-\sqrt{237.16}}{2*-4.9}=\frac{-14-\sqrt{237.16}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+\sqrt{237.16}}{2*-4.9}=\frac{-14+\sqrt{237.16}}{-9.8}
$