Sоlve the equаtiоn. Give а generаl fоrmula for all the solutions.
A 25-yeаr-оld wоmаn is evаluated fоr “gas pains” that began 7 months ago. The pain has been increasing in frequency with episodes now occurring at least twice each week for the past 3 months. The pain is diffuse and non-radiating, lasts several hours, and is typically relieved with bowel movements. She has two bowel movements weekly, sometimes with lumpy stools and at other times with loose stools. She has not noted any blood in her bowel movements and does not have nocturnal pain or weight loss. Medical history is significant only for occasional episodes of mild depression. She takes no medications. There is no family history of colon cancer or other bowel-related diseases. On physical examination, vital signs are normal. Body mass index is 26. Abdominal examination discloses normal bowel sounds and no evidence of guarding or rebound tenderness. There is firm stool present in the rectal vault. Complete blood count is normal. Which of the following is the most likely cause of her abdominal pain?