4.9t^2-12t-69=0

Solution for 4.9t^2-12t-69=0 equation:

4.9t^2-12t-69=0

a = 4.9; b = -12; c = -69;
Δ = b2-4ac
Δ = -122-4·4.9·(-69)
Δ = 1496.4
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{-(-12)-\sqrt{1496.4}}{2*4.9}=\frac{12-\sqrt{1496.4}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+\sqrt{1496.4}}{2*4.9}=\frac{12+\sqrt{1496.4}}{9.8}
$