Marin writes the functions m(x) = StartFraction 3 x Over x + 7 EndFraction and n(x) = StartFraction 7 x Over 3 minus x EndFraction. Which equation must be true for m(x) and n(x) to be inverse functions? StartStartFraction 3 (StartFraction 3 x Over x + 7 EndFraction) OverOver (StartFraction 3 x Over x + 7 EndFraction) + 7 EndEndFraction = StartStartFraction 7 (StartFraction 7 x Over 3 minus x EndFraction) OverOver 3 minus (StartFraction 7 x Over 3 minus x EndFraction) EndEndFraction = x StartStartFraction 3 (StartFraction 7 x Over 3 minus x EndFraction) OverOver (StartFraction 7 x Over 3 minus x EndFraction) + 7 EndEndFraction = StartStartFraction 7 (StartFraction 3 x Over x + 7 EndFraction) OverOver 3 minus (StartFraction 3 x Over x + 7 EndFraction) EndEndFraction = x StartStartFraction 3 (StartFraction 3 x Over x + 7 EndFraction) OverOver (StartFraction 3 x Over x + 7 EndFraction) + 7 EndEndFraction = StartStartFraction 7 (StartFraction 7 x Over 3 minus x EndFraction) OverOver 3 minus (StartFraction 7 x Over 3 minus x EndFraction) EndEndFraction = 0 StartStartFraction 3 (StartFraction 7 x Over 3 minus x EndFraction) OverOver (StartFraction 7 x Over 3 minus x EndFraction) + 7 EndEndFraction = StartStartFraction 7 (StartFraction 3 x Over x + 7 EndFraction) OverOver 3 minus (StartFraction 3 x Over x + 7 EndFraction) EndEndFraction = 0