P1:

`(-5/8)xx3/11+13/18xx3/11-2/11`

`=3/11xx(-5/8+13/18)-2/11`

`=3/11xx7/72-2/11`

`=7/264-2/11`

`=-41/264`

P2:

`2/3+0,75+11/13-0,75`

`=2/3+(0,75-0,75)+11/13`

`=2/3+11/13`

`=59/39`

P3:

`1/2xx8/5-1/2xx3/5`

`=1/2xx(8/5-3/5)`

`=1/2xx5/5`

`=1/2xx1`

`=1/2`

P4:

`(-2/5)+x=1/3`

`x=1/3+2/5`

`x=11/15`

P5:

`(2/15:x)xx1/5=-3/5`

`2/15:x=-3/5:1/5`

`2/15:x=-3`

`x=2/15:(-3)`

`x=-2/45`

P6:

`7/5:14/25-7/10`

`=7/5xx25/14-7/10`

`=5/2-7/10`

`=25/10-7/10`

`=18/10`

`=9/5`

P7:

`2x-1/3=11/9`

`2x=11/9+1/3`

`2x=11/9+3/9`

`2x=14/9`

`x=14/9:2`

`x=7/9`