solve -4.9t^2+3t+1.7
Setting the quadratic to zero,
-4.9t^2 + 3t + 1.7 = 0
This equation has no has no obvious factors, so use the quadratic formula.
t = (-b +/- sqrt(b^2 - 4ac))/)2a)
where a = -4.9, b = 3, c = 1.7 from ax^2 + bx + c = -4.9t^2 + 3t + 1.7
t = (-3 +/- sqrt(3^2 - 4(-4.9)(1.7)))/(2*(-4.9))
t = (-3 +/- sqrt(9 + 33.32))/(-9.8)
t = (-3 +/- sqrt(42.32))/(-9.8)
t = (-3 +/- 6.5054)/(-9.8)
t = 0.969937, t = -0.357692