negative values will be positive, so I don't see any other numbers

but is it possible to multiply numerator and denominator by x like this?

3x/x(1 +(4/x^2))^(1/2)

then I enter the x inside the root x^2 which will lead to

3x/(x^2 + 4)^(1/2)

then I will have no problem when the x = 0