已知2a^2+a-4=0a-b=2求a+1分之1+b分之2的值
1个回答
展开全部
由2a²+a-4=0得a=4-2a²
由a-b=2得b=a-2
1/(a+1) +2/b
=(b+2a+2)/[(a+1)b]
=(a-2+2a+2)/[(a+1)(a-2)]
=3a/(a²-a-2)
=3(4-2a²)/[a²-(4-2a²)-2]
=-6(a²-2)/[3(a²-2)]
=-2
由a-b=2得b=a-2
1/(a+1) +2/b
=(b+2a+2)/[(a+1)b]
=(a-2+2a+2)/[(a+1)(a-2)]
=3a/(a²-a-2)
=3(4-2a²)/[a²-(4-2a²)-2]
=-6(a²-2)/[3(a²-2)]
=-2
已赞过
已踩过<
评论
收起
你对这个回答的评价是？
推荐律师服务：
若未解决您的问题，请您详细描述您的问题，通过百度律临进行免费专业咨询
