Page3CS165, Practice Midterm Problems, Spring 2020EXPRESSION TREES – 1Using the expression tree shown below, answer the following questions:1.Show the postfix expression represented by the tree, with spaces between each token, and noleading or trailing spaces.2.Show the infix expression represented by the tree, with spaces between each token, and no leadingor trailing spaces.3.Show the prefix expression represented by the tree, with spaces between each token, and noleading or trailing spaces.4.What does the expression evaluate to, assuming integer math and the normal Java order ofoperations, which are of course reflected in the prefix and postfix forms and the tree? Do this usingthe tree, and verify the answer using the infix expression.