0=-16t^2+64t+336

Solution for 0=-16t^2+64t+336 equation:

0=-16t^2+64t+336

We move all terms to the left:

0-(-16t^2+64t+336)=0

We add all the numbers together, and all the variables

-(-16t^2+64t+336)=0

We get rid of parentheses

16t^2-64t-336=0

a = 16; b = -64; c = -336;
Δ = b2-4ac
Δ = -642-4·16·(-336)
Δ = 25600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25600}=160$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-160}{2*16}=\frac{-96}{32}
=-3
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+160}{2*16}=\frac{224}{32}
=7
$