Question

用反证法证明“若x≠1且x≠2，则x²-3x+2≠0”时的假设应为（    ）

A.x=1或x=2                              B.x²-3x+2=0

C.x²-3x+2≤0                           D.x²-3x+2＞0

Answer 1

解析:用反证法证明命题的假设是原命题结论的否定，即“x²-3x+2=0”.

答案:B.