-4.9t^2+5t+1.7=0

Solution for -4.9t^2+5t+1.7=0 equation:

-4.9t^2+5t+1.7=0

a = -4.9; b = 5; c = +1.7;
Δ = b2-4ac
Δ = 52-4·(-4.9)·1.7
Δ = 58.32
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{-(5)-\sqrt{58.32}}{2*-4.9}=\frac{-5-\sqrt{58.32}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{58.32}}{2*-4.9}=\frac{-5+\sqrt{58.32}}{-9.8}
$