4.9t^2-3t-165=0

Solution for 4.9t^2-3t-165=0 equation:

4.9t^2-3t-165=0

a = 4.9; b = -3; c = -165;
Δ = b2-4ac
Δ = -32-4·4.9·(-165)
Δ = 3243
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:

$\sqrt{\Delta}=\sqrt{3243}=\sqrt{1*3243}=\sqrt{1}*\sqrt{3243}=1\sqrt{3243}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-1\sqrt{3243}}{2*4.9}=\frac{3-1\sqrt{3243}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+1\sqrt{3243}}{2*4.9}=\frac{3+1\sqrt{3243}}{9.8}
$