1. (y^2 + 3) dx - (e^x / x) ydy = 0. 2. y' + y + y^2 = 0. 3. y^2 + x^2y' = xyy' 4. y' - y = e^x, y(1) = 1 / 20 5. xy' + 2y + x^(5/3) e^x = 0.