Exercise 1 (8 points): Consider the B+ tree index shown in the figure below. Each intermediate node can hold up to five pointers and four key values. Each leaf can hold up to four records, and leaf nodes are doubly linked as usual, although these links are not shown in the figure. Answer the following questions. Please show every step of the insertion and explain the process. 3 180 354250 63 # 12 031 99100 105 5 94 95 96 97 L2 L4 L7 42 43 L3 L6 (1). Insert a record with search key 109 into the tree. (4 points) (2). Delete the record with search key 81 from the original tree. (4 points)