Calculations Theory

Assign = + - * / + ( ) ID | | A|B|C|... Zlable... ZILI$ 0|1|2|3|41516171819 A) Are these strings accepted? Why? a. Hh = $redi + _R_ b. lbb=r+tt5 - 57 B) Derive the string rl =s+t-(+y) C) Is the grammar ambiguous? Why