4.9t^2-17.5t+6.6=0

Solution for 4.9t^2-17.5t+6.6=0 equation:

4.9t^2-17.5t+6.6=0

a = 4.9; b = -17.5; c = +6.6;
Δ = b2-4ac
Δ = -17.52-4·4.9·6.6
Δ = 176.89
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{-(-17.5)-\sqrt{176.89}}{2*4.9}=\frac{17.5-\sqrt{176.89}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17.5)+\sqrt{176.89}}{2*4.9}=\frac{17.5+\sqrt{176.89}}{9.8}
$