0=4+64t-16t^2

Solution for 0=4+64t-16t^2 equation:

0=4+64t-16t^2

We move all terms to the left:

0-(4+64t-16t^2)=0

We add all the numbers together, and all the variables

-(4+64t-16t^2)=0

We get rid of parentheses

16t^2-64t-4=0

a = 16; b = -64; c = -4;
Δ = b2-4ac
Δ = -642-4·16·(-4)
Δ = 4352
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:

$\sqrt{\Delta}=\sqrt{4352}=\sqrt{256*17}=\sqrt{256}*\sqrt{17}=16\sqrt{17}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-16\sqrt{17}}{2*16}=\frac{64-16\sqrt{17}}{32}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+16\sqrt{17}}{2*16}=\frac{64+16\sqrt{17}}{32}
$