Which of the following equations is both separable and linear?
dydx=x+y\frac{dy}{dx} = x + ydxdy=x+y
dydx=xy\frac{dy}{dx} = xydxdy=xy
dydx=x2\frac{dy}{dx} = x^2dxdy=x2
dydx=y2\frac{dy}{dx} = y^2dxdy=y2