-4.9t^2-2t+45=0

Solution for -4.9t^2-2t+45=0 equation:

-4.9t^2-2t+45=0

a = -4.9; b = -2; c = +45;
Δ = b2-4ac
Δ = -22-4·(-4.9)·45
Δ = 886
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:

$\sqrt{\Delta}=\sqrt{886}=\sqrt{1*886}=\sqrt{1}*\sqrt{886}=1\sqrt{886}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-1\sqrt{886}}{2*-4.9}=\frac{2-1\sqrt{886}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+1\sqrt{886}}{2*-4.9}=\frac{2+1\sqrt{886}}{-9.8}
$