300=-16x^2+64x+336

Solution for 300=-16x^2+64x+336 equation:

300=-16x^2+64x+336

We move all terms to the left:

300-(-16x^2+64x+336)=0

We get rid of parentheses

16x^2-64x-336+300=0

We add all the numbers together, and all the variables

16x^2-64x-36=0

a = 16; b = -64; c = -36;
Δ = b2-4ac
Δ = -642-4·16·(-36)
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-80}{2*16}=\frac{-16}{32}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+80}{2*16}=\frac{144}{32}
=4+1/2
$