-16t^2+76t+11=0

Solution for -16t^2+76t+11=0 equation:

-16t^2+76t+11=0

a = -16; b = 76; c = +11;
Δ = b2-4ac
Δ = 762-4·(-16)·11
Δ = 6480
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:

$\sqrt{\Delta}=\sqrt{6480}=\sqrt{1296*5}=\sqrt{1296}*\sqrt{5}=36\sqrt{5}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(76)-36\sqrt{5}}{2*-16}=\frac{-76-36\sqrt{5}}{-32}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(76)+36\sqrt{5}}{2*-16}=\frac{-76+36\sqrt{5}}{-32}
$