dydx+Py=Q\dfrac{dy}{dx} + Py = Qdxdy+Py=Q: IF =e∫Pdx= e^{\int P dx}=e∫Pdx; y⋅IF=∫Q⋅IF dx+Cy \cdot \text{IF} = \int Q \cdot \text{IF}\, dx + Cy⋅IF=∫Q⋅IFdx+C.