8.已知$\frac{1}{x}$+$\frac{1}{y}$=3,则分式$\frac{2x-3xy+2y}{x+2xy+y}$的值为( )
| A. | $\frac{3}{5}$ | B. | 9 | C. | 1 | D. | 不能确定 |
7.先化简,再求值.
(1)3(x2-2x-1)-4(3x-2)+2(x-1),其中x=-3
(2)2(2a2b+3ab2)-3(a2b-1)-2ab2-2,其中a=-1,b=$\frac{1}{2}$.
0 289945 289953 289959 289963 289969 289971 289975 289981 289983 289989 289995 289999 290001 290005 290011 290013 290019 290023 290025 290029 290031 290035 290037 290039 290040 290041 290043 290044 290045 290047 290049 290053 290055 290059 290061 290065 290071 290073 290079 290083 290085 290089 290095 290101 290103 290109 290113 290115 290121 290125 290131 290139 366461
(1)3(x2-2x-1)-4(3x-2)+2(x-1),其中x=-3
(2)2(2a2b+3ab2)-3(a2b-1)-2ab2-2,其中a=-1,b=$\frac{1}{2}$.