Simplify: \ac1x+\ac1y\ac{1}{x} + \ac{1}{y}\ac1x+\ac1y as a single fraction.
\acx+yxy\ac{x + y}{xy}\acx+yxy
\ac2x+y\ac{2}{x + y}\ac2x+y
\ac1xy\ac{1}{xy}\ac1xy
\acxyx+y\ac{xy}{x + y}\acxyx+y