200=5x^2-25

Solution for 200=5x^2-25 equation:

200=5x^2-25

We move all terms to the left:

200-(5x^2-25)=0

We get rid of parentheses

-5x^2+25+200=0

We add all the numbers together, and all the variables

-5x^2+225=0

a = -5; b = 0; c = +225;
Δ = b2-4ac
Δ = 02-4·(-5)·225
Δ = 4500
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:

$\sqrt{\Delta}=\sqrt{4500}=\sqrt{900*5}=\sqrt{900}*\sqrt{5}=30\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-30\sqrt{5}}{2*-5}=\frac{0-30\sqrt{5}}{-10}
=-\frac{30\sqrt{5}}{-10}
=-\frac{3\sqrt{5}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+30\sqrt{5}}{2*-5}=\frac{0+30\sqrt{5}}{-10}
=\frac{30\sqrt{5}}{-10}
=\frac{3\sqrt{5}}{-1}
$