Solve the following Diffrential Equation $(x+y+1)dx+(2x+2y-1)dy=0$ I want to seperate variables in the following equation and need some advice:
$$(x+y+1)dx+(2x+2y-1)dy=0$$
what I tried to do so far is:
$$ydx+(x+1)dx+(2y-1)dy+2xdy=0$$
now how I should I continue? thanks.

Hint:
Setting $$(x+y+1)=u\longrightarrow 2x+2y-1=2u-3,~~~dx+dy=du$$ makes your ODE separable.
