Consider the following grammar G6 from the book:

::= + |

::= * |

::= ( ) | a | b | c

(a) Draw a parse tree for the following expression: a * (b + c)

(b) Modify grammar G6 by adding subtraction and division operators (- and /) with customary precedence and associativity.

(c) Modify the grammar from (b) by adding a right associative operator = at lower precedence than any other operators.