Answer the following questions about Stacks. (i). Assume that we have an empty stack . A series of stack operations are performed on stack . The elements are pushed into in the order of { 1, 3, 9, 6, 7 }. The elements are poped out of in the order of { 9, 3, 6, 1, 7 }. Please write down the sequence of stack operations performed on .

(ii). Given the postfix expression 5 7 + 3 * 8 4 / -, show how to use a stack to calculate the final results. Please show the stack status step by step.

(iii). Use a stack to check if the symbol list ( { [ ] } [ ] ) is balanced. Show the stack status after each symbol checking.