The Tree Data Model

Give expression trees for the following expressions. Note that, as is cus- tomary with expressions, we have omitted redundant parentheses. You must first restore the proper pairs of parentheses, using the customary rules for precedence and associativity of operators. a) (x + 1) (x y + 4) b) 1 + 2 + 3 + 4 + 5 + 6 c) 9 8 + 7 6 + 5