19х * 3у * (5-25х) * 4у * (3-30х) * 2у * 6 =
19х * 3у * 4у * 2у * 6 * (5-25х) * (3-30х) =
2736ху³ * (5-25х) * (3-30х) =
(2736ху³ * 5 - 2736ху³ * 25х) * (3-30х) =
(13680ху³ - 68400х²у³) * (3-30х) =
13680ху³*3 - 13680ху³*30х - 68400х²у³*3 + 68400х²у³* 30х =
41040ху³- 410400х²у³ - 205200х²у³ + 2052000х³у³ =
41040ху³- 615600х²у³ + 2052000х³у³