已知1/a+1/b=3,则a−ab+ba+2ab+b的值是_.
问题描述:
已知
+1 a
=3,则1 b
的值是______. a−ab+b a+2ab+b
答
∵
+1 a
=3,1 b
∴a+b=3ab,
∴
=a−ab+b a+2ab+b
=2ab 5ab
.2 5
故答案为:
.2 5