What is the integrating factor for the equation y′+2xy=3y' + \frac{2}{x}y = 3y′+x2y=3?
μ(x)=x\mu(x) = xμ(x)=x
μ(x)=x2\mu(x) = x^2μ(x)=x2
μ(x)=1/x2\mu(x) = 1/x^2μ(x)=1/x2
μ(x)=2x\mu(x) = 2xμ(x)=2x