`# Ly`

`a)`

      `(11 . 3^22 . 3^7 - 9^15)/((2 . 3^14)^2)`

`= (11 . 3^22 . 3^7 - (3^2)^15)/(2^2 . (3^14)^2)` 

`= (11 . 3^29 - 3^30)/(2^2 . 3^28)` 

`= (3^29 . (11 - 3))/(2^2 . 3^28)`

`= (3 . 8)/4`

`= 3. 2`

`= 6`

`b)`

        `(2^10 . 3^10 - 2^10 . 3^9)/(2^9 . 3^10)`

`= (2^10 . 3^9 . (3 - 1))/(2^9 . 3^10)`

`= (2. 2)/3`

`= 4/3`

`c)`

          `(4^5 . 9^4 - 2. 6^9)/(2^10 . 3^8 + 6^8 . 20)`

`= ((2^2)^5 . (3^2)^4 - 2. (2.3)^9)/(2^10 . 3^8 + (2.3)^8 . (2^2 . 5))`

`= (2^10 . 3^8 - 2. 2^9 .3^9)/(2^10 . 3^8 + 2^8 .3^8 . 2^2 . 5)`

`= (2^10 . 3^8 - 2^10 .3^9)/(2^10 . 3^8 + 2^10 .3^8 . 5)`

`= (2^10 . 3^8 . (1 - 3))/(2^10 . 3^8 . (1+5))`

`= (-2)/6`

`= -1/3`