You can put this solution on YOUR website!
y = 1/(5-2x)
y = (5-2x)^(-1)
dy/dx = -1*(5-2x)^(-2)*d/dx[5-2x]
dy/dx = -1*(5-2x)^(-2)*(-2)
dy/dx = 2(5-2x)^(-2)
dy/dx = 2/( (5-2x)^2 )
Optionally you can expand out the denominator if you wanted to.
In the third step, I used the power rule going from y = x^n to dy/dx = nx^(n-1). I also used the chain rule to apply the derivative to the inner piece 5-2x.