题目

Two good friends, Sam and Jason, met with a car accident on their way home one snowy night. The next morning, Sam woke up blind. His legs were broken. The doctor, Mr Lee, was standing by his bed, looking at him worriedly. When he saw Sam awake, he asked, “How are you feeling, Sam?” Sam smiled and said, “Not bad, Doctor. Thank you very much for doing the special operation(手术).” Mr Lee was moved by Sam. When he was leaving, Sam said, “Please don’t tell Jason about it.” “Well…Well…OK,” Mr Lee replied. Months later when Jason’s wounds healed(愈合), Sam was still very 已知最简二次根式与的被开方数相同，则a=    ．