题目

若a-b=3，ab=1，则a2+b2=______． 答案：【答案】11．【解析】根据题意，把a-b=3两边同时平方可得，a2-2ab+b2=9，结合题意，将a2+b2看成整体，求解即可．∵a-b=3，ab=1， ∴（a-b）2=a2-2ab+b2=9， ∴a2+b2=9+2ab=9+2=11． 故答案为11．—What's wrong you? （ ）—I think I hurt my leg.A. to B. with C. for