What is the integrating factor μ(x)\mu(x)μ(x) for the linear differential equation y′+5xy=7x2y' + \frac{5}{x}y = 7x^2y′+x5y=7x2?
μ(x)=5x\mu(x) = 5xμ(x)=5x
μ(x)=x5\mu(x) = x^5μ(x)=x5
μ(x)=e5x\mu(x) = e^{5x}μ(x)=e5x
μ(x)=ln(x5)\mu(x) = \ln(x^5)μ(x)=ln(x5)