-16t^2-100t+15=0

Solution for -16t^2-100t+15=0 equation:

-16t^2-100t+15=0

a = -16; b = -100; c = +15;
Δ = b2-4ac
Δ = -1002-4·(-16)·15
Δ = 10960
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:

$\sqrt{\Delta}=\sqrt{10960}=\sqrt{16*685}=\sqrt{16}*\sqrt{685}=4\sqrt{685}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-100)-4\sqrt{685}}{2*-16}=\frac{100-4\sqrt{685}}{-32}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-100)+4\sqrt{685}}{2*-16}=\frac{100+4\sqrt{685}}{-32}
$