Bài 2 : 

`a)` `(x^2-y^2)/(6x^2y):(x+y)/(3xy)`

`=` `\frac{(x-y).(x+y)}{6x^2y}*(3xy)/(x+y)`

`=` `(x-y)/(2x)`

`b)` `(5x-15)/(4x+4):(x^2-9)/(x^2+2x+1)`

`=` `\frac{5*(x-3)}{4*(x+1)}*[(x+1)^2]/[(x-3).(x+3)]`

`=` `\frac{5*(x+1)}{4*(x+3)}`

`c)` `(6x+48)/(7x-7):(x^2-64)/(x^2-2x+1)`

`=` `\frac{6*(x+8)}{7*(x-1)}*\frac{(x-1)^2}{(x-8).(x+8)}`

`=` `\frac{6*(x-1)}{7*(x-8)}`

`d)` `(4x-24)/(5x+5):(x^2-36)/(x^2+2x+1)`

`=` `\frac{4*(x-6)}{5*(x+1)}*\frac{(x+1)^2}{(x-6).(x+6)}`

`=` `\frac{4*(x+1)}{5*(x+6)}`

`e)` `(3x+21)/(5x+5):(x^2-49)/(x^2+2x+1)`

`=` `\frac{3*(x+7)}{5*(x+1)}*\frac{(x+1)^2}{(x-7).(x+7)}`

`=` `\frac{3*(x+1)}{5*(x-7)}`