Compute the general solution of the linear inhomogeneous differential equation y' = .
It doesn't help to find the integrating factor if you don't know what an "integrating factor" is! Don't memorize formulas, learn concepts!
An integrating factor for a linear differential equation of the form dy/dx+P(x)y= f(x,y) is a function of x, such that multiplying both sides of the equation by it converts the left side into a "perfect" derivative so that the equation becomes: .
If (1+ x) really is an integrating equation (I haven't checked that) then multiplying 1+x on both sides converts the equation to . Now integrate both sides with respect to x.