सरल कीजिए
`(r^(2)+s^(2)+2rs-9t^(2))/(a^(3)-27b^(3)+64c^(3)+36abc)div(r+s-3t)/(a^(2)+9b^(2)+16c^(2)+3ab+12bc-4ac)`

Answer

`(r+s+3t)/(a-3b+4c)`