a^2+3a+1=0...① b^2+3b+1=0...② ①-②,得a^2-b^2=-3(a-b) (a+b)(a-b)=-3(a-b) a不等于b a+b=-3 ①+②,得a^2+b^2+3(a+b)+2=0 a^2+b^2-9+2=0 a^2+b^2=7 (a+b)^2=9 a^2+2ab+b^2=9 2ab=2 ab=1 a^b+ab^=ab(a+b)=-3 1\a+1\b=(a+b)/ab=-3/1=-3 ab=1 a^2 b