1、已知:1/a+1/b=4,求(a-3ab+b)/(2a-7ab+2b)的值 2、已知:1/x-1/y=3,求(2x+3xy-2y)/(x-2xy-y)的值
问题描述:
1、已知:1/a+1/b=4,求(a-3ab+b)/(2a-7ab+2b)的值 2、已知:1/x-1/y=3,求(2x+3xy-2y)/(x-2xy-y)的值
要求:1、根据(人教版初二下册第十六章)《分式》的方法来做;
答
1/a+1/b=4a+b=4ab
(a-3ab+b)/(2a-7ab+2b)
=(4ab-3ab)/(8ab-7ab)
=ab/ab
=1
1/x-1/y=3x-y=3xy
(2x+3xy-2y)/(x-2xy-y)
=(6xy+3xy)/(3xy-2xy)
=9xy/xy
=9