(a2-a)a2-2a-3÷a(a-3)=a(a-1)(a+1)(a

(a2-a)a2-2a-3÷a(a-3)=a(a-1)(a+1)(a [1-(6+3a)/(a2+4a+4)]÷[(4a-4)/(a2+2a)] （a-1)-(3a2-2a+1) 已知实数a满足a2+2a-1=0求(1 /a+1)-(a+3/a2-1)*(a2-2a+1/a2+4a+3)的值 (a2-1)/(a2+2a+1)除以(a2-a)/(a+1) (a-2/(a+3)除以(a2-4)/(a2+6a+9) 设a=根号3-3,求[(a+1/a2-a)+(4/1-a2)]除以(a2+2a-3/a2+3a)的值 先化简,后求值:a2-2a+1分之a2-1+a-2分之2a-a2÷a,其中a=2分之3 （a2-4/a2-4a+3）×（a-3/a2+3a+2=? 先化简,再求值(3a/a-1 -a/a+1)(a2-1/a),其中a=根号2-2 已知A=-a-1，B=a2+a，C=2a2-5a-1 已知a2+3a+1=0 求   1+1/a a2+1/a2 已知a=1/2+根号3,求a2-a-6/a+2 - 根号a2-2a+1/a2-a的值