100=300-16x^2

Solution for 100=300-16x^2 equation:

100=300-16x^2

We move all terms to the left:

100-(300-16x^2)=0

We get rid of parentheses

16x^2-300+100=0

We add all the numbers together, and all the variables

16x^2-200=0

a = 16; b = 0; c = -200;
Δ = b2-4ac
Δ = 02-4·16·(-200)
Δ = 12800
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{12800}=\sqrt{6400*2}=\sqrt{6400}*\sqrt{2}=80\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-80\sqrt{2}}{2*16}=\frac{0-80\sqrt{2}}{32}
=-\frac{80\sqrt{2}}{32}
=-\frac{5\sqrt{2}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+80\sqrt{2}}{2*16}=\frac{0+80\sqrt{2}}{32}
=\frac{80\sqrt{2}}{32}
=\frac{5\sqrt{2}}{2}
$