-16t2+8t+15=0

Solution for -16t2+8t+15=0 equation:

-16t^2+8t+15=0

a = -16; b = 8; c = +15;
Δ = b2-4ac
Δ = 82-4·(-16)·15
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-32}{2*-16}=\frac{-40}{-32}
=1+1/4
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+32}{2*-16}=\frac{24}{-32}
=-3/4
$