Saved Bookmarks
| 1. |
If 3x + 2y = 9 and xy = 3, find : 27x3 + 8y3 |
|
Answer» 27x3 + 8y3 = (3x)3 + (2y)3 = (2x + 2y)3 - 3. 3x . 2y (3x + 2y) (3x - 2y)3 - 18xy (3x + 2y) = (9)3 - 18(3) (9) = 729 - 486 = 243 |
|