因为：a=3+2√2,b=3-2√2所以：a-b=4√2;ab=(3-2√2)(3+2√2)=9-8=1所以：a�0�5b-ab�0�5=ab(a-b)=4√2.
a2b-ab=ab*(a-1)=14+7跟号2 ab=9-2=7
