**Background**

We know that the first order differential equation in the form 
$$\frac{dy}{dx}+p(x)y=q(x)$$
is amenable to the method of integrating factor

**Question** 

How is this first order equation amenable to the method of integrating factor? The equation seems not to be in the desired form. 

$$y^{\prime}+y=\frac{2 x e^{-x}}{1+y e^{x}}$$