X(10x-25)=200

Solution for X(10x-25)=200 equation:

X(10X-25)=200

We move all terms to the left:

X(10X-25)-(200)=0

We multiply parentheses

10X^2-25X-200=0

a = 10; b = -25; c = -200;
Δ = b2-4ac
Δ = -252-4·10·(-200)
Δ = 8625
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:

$\sqrt{\Delta}=\sqrt{8625}=\sqrt{25*345}=\sqrt{25}*\sqrt{345}=5\sqrt{345}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-5\sqrt{345}}{2*10}=\frac{25-5\sqrt{345}}{20}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+5\sqrt{345}}{2*10}=\frac{25+5\sqrt{345}}{20}
$