First you must take into account the variable that is being defined for this case: c = represents the number of puppies whose eyes are closed. We can then write the following equation: 15 = 11 + c Rewriting the equation: 11 + c = 15 Clearing c: c = 15-11 c = 4 4 puppies have their eyes closed Answer: 11 + c = 15 4 puppies have their eyes closed