根号（a2-3a+1）+b2+2b+1=0,
则a^2-3a+1=0且b^2+2b+1=0
所以a+1/a=3,b=-1
a^2+1/a^2=（a+1/a）^2-2=7
a^2+1/a^2-绝对值b=6