avl trees rotations question
Apparently, you want to rebalance the AVL tree. 

You can either do a simple left rotation or a right-left rotation. 

I prefer not to mention right-right rotation since that term is misleading and ambiguous.

You can visualize what is happening. Go to AVL tree visualization, a page created by David Galles. Insert 2, 1, 4, 3, 5 in that order. Now look closely when you delete 1.