a=-(1/(2+√5)=2-√5
(9-6a+a²)/(a-3)+√(a²-2a+1)/(a²-a)
=(a-3)²/(a-3)+√(a-1)²/a(a-1)
=a-3+(a-1)/a(a-1)
=a+3+1/a
=2-√5+3+1/(2-√5)
=5-√5-(2+√5)
=5-√5-2-√5
=3-2√5原式好像应该=a-3-1/a啊 你符号错了 再算算 别去网上找别人的a=-(1/(2+√5)=2-√5(9-6a+a²)/(a-3)-√(a²-2a+1)/(a²-a)=(a-3)²/(a-3)-√(a-1)²/a(a-1)=a-3-(a-1)/a(a-1)=a-3-1/a=2-√5-3-1/(2-√5)=-1-√5+(2+√5)=-1-√5+2+√5=1的确是符号错了