Bài 1 (2,0 điểm) a) Thực hiện phép tính: $\frac{9}{81}$+ $\frac{1}{2}$ -$ \frac{1}{9}$  b) Tính hợp lý: $\frac{5}{7}$. $\frac{12}{17}$ + $\frac{5}{7}$. $\frac{5}{17}$  c) Tim x: $\frac{3}{5}$+ $\frac{2}{3}x$ = $1\frac{1}{3}$ 

Bài 1:

`a)9/81 + 1/2 - 1/9`

`=1/9 + 1/2 - 1/9`

`=1/9 - 1/9 + 1/2`

`=0+1/2`

`=1/2`

`b)5/7 xx 12/17 + 5/7 xx 5/17`

`=5/7 xx (12/17 + 5/17)`

`=5/7 xx 1`

`=5/7`

`c)3/5 + 2/3x = 1 1/3`

`2/3x = 4/3 - 3/5`

`2/3x = 11/15

`x = 11/15 ÷ 2/3`

`x = 11/15 xx 3/2`

`x = 11/10`

Vậy `x=11/10`