`a) 5 2/7 .8/11 +5 2/7 .5/11 -5 2/7 .2/11`
`=5 2/7.(8/11 +5/11 -2/11)`
`= 37/7. 11/11`
`=37/7 .1`
`=37/7`
`b) 2 3/4 .(-0,4) -1 3/5 .2,75 +(-1,2) :4/11`
`= 11/4 .-2/5 - 8/5 .11/4 - 6/5 .11/4`
`=11/4.(-2/5 -8/5 -6/5)`
`=11/4. -16/5=-44/5`
`c) (5. 27^3 .4^5)/6^5 :( (5^5 .2^4)/10^4 .(2^6 .3^4)/6^4 )`
`=(5 .(3^3)^3 .(2^2)^5)/(2.3)^5) : ( (5 .5^4. 2^4)/(2 . 5)^4 . (2^2 . 2^4 .3^4)/(2 .3)^4 )`
`=( 5 . 3^9 .2^10/2^5 .3^5) : ( (5 . 5^4 .2^4)/(2^4 .5^4) . (2^2 .2^4 . 3^4)/(2^4 .3^4) )`
`=5 . 3^4 . 2^5 :(5 .2^2)`
`=81 .8=648`
`d) (5 - 5/3 -5/9 -5/27)/(8 - 8/3 -8/9 -8^27) : (15 - 15/11 +15/121)/(16 -16/11 +16/121)`
`= (5.(1 -1/3 -1/9 -1/27))/(8.(1 -1/3 -1/9 -1/27)) : (15 .(1- 1/11 +1/121))/(16.(1 -1/11 +1/121))`
`=5/8 : 15/16=5/8 .16/15=2/3`