赞 薇儿 花朵
共回答了23个问题采纳率：78.3% 举报
[(a-2)/(a^2+2a)-(a-1)/(a^2+4a+4)]÷(a-4)/(a+2)
=[(a-2)/a(a+2)-(a-1)/(a+2)^2]÷(a-4)/(a+2)
=[(a-2)/a(a+2)-(a-1)/(a+2)^2]*(a+2)/(a-4)
=(a-2)/a(a+2)*(a+2)/(a-4)-(a-1)/(a+2)^2*(a+2)/(a-4)
=(a-2)/a(a-4)-(a-1)/(a+2)(a-4)
=(a-2)(a+2)/a(a+2)(a-4)-a(a-1)/a(a+2)(a-4)
=[(a-2)(a+2)-a(a-1)]/a(a+2)(a-4)
=(a^2-4-a^2+a)/a(a+2)(a-4)
=(a-4)/a(a+2)(a-4)
=1/a(a+2)
=1/[-12*(-12+2)]
=1/120
=[(a-2)/a(a+2)-(a-1)/(a+2)^2]÷(a-4)/(a+2)
=[(a-2)/a(a+2)-(a-1)/(a+2)^2]*(a+2)/(a-4)
=(a-2)/a(a+2)*(a+2)/(a-4)-(a-1)/(a+2)^2*(a+2)/(a-4)
=(a-2)/a(a-4)-(a-1)/(a+2)(a-4)
=(a-2)(a+2)/a(a+2)(a-4)-a(a-1)/a(a+2)(a-4)
=[(a-2)(a+2)-a(a-1)]/a(a+2)(a-4)
=(a^2-4-a^2+a)/a(a+2)(a-4)
=(a-4)/a(a+2)(a-4)
=1/a(a+2)
=1/[-12*(-12+2)]
=1/120
1年前
3
可能相似的问题
-
1年前1个回答
-
化简求值（4a²-2a-6)-2(2a²-2a-5）其中a=-1
1年前2个回答
-
化简求值：（2-a2+4a）-（5a2-a-1），其中a=-2．
1年前1个回答
-
化简求值:(1/4a^2-b^2)【ab-(1/2a+b)^2】
1年前3个回答
你能帮帮他们吗