Thực hiện phép tính: `9,` `(3x^3y^4)^2:(-2x^5y^6)` `10,` `5/4x^4y^3:1/3x^3y^3` `11,` `3/4x^3y^3:(-1/2x^2y^2)` `12,` `3/4(x^2y)^2:1/8xy^2`

`9, ( 3x^3 y^4 )^2 : ( -2x^5 y^6 )`

`= 9 x^6 y^8 : ( -2 x^5 y^6 )`

`= [ 9 : ( -2 ) ] . ( x^6 : x^5 ) . ( y^8 : y^6 )`

`= -9/2 x y^2`

`10, 5/4 x^4 y^3 : 1/3 x^3 y^3`

`= ( 5/4 : 1/3 ) . ( x^4 : x^3 ) . ( y^3 : y^3 )`

`= 15/4 x`

`11 , 3/4 x^3 y^3 : ( -1/2 x^2 y^2 )`

`= [ 3/4 : ( -1/2 ) ] . ( x^3 : x^2 ) . ( y^3 : y^2 )`

`= -3/2 x y`

`12, 3/4 ( x^2 y )^2 : 1/8 xy^2`

`= 3/4 x^4 y^2 : 1/8 xy^2`

`= ( 3/4 : 1/8 ) . ( x^4 : x ) . ( y^2 : y^2 )`

`= 6 x^3`