-16t^2-64t+60=0

Solution for -16t^2-64t+60=0 equation:

-16t^2-64t+60=0

a = -16; b = -64; c = +60;
Δ = b2-4ac
Δ = -642-4·(-16)·60
Δ = 7936
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:

$\sqrt{\Delta}=\sqrt{7936}=\sqrt{256*31}=\sqrt{256}*\sqrt{31}=16\sqrt{31}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-16\sqrt{31}}{2*-16}=\frac{64-16\sqrt{31}}{-32}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+16\sqrt{31}}{2*-16}=\frac{64+16\sqrt{31}}{-32}
$