Remember that the expression for part (a) is x + 1 + x.
If you put in the value for x and simplified the expression, what answer would you get?
Try the problem on your own before checking the answer.
Look back at part (b) of 4-122. Using the expression you wrote, substitute 4 for ''m'' and simplify the expression.
This problem is very similar to parts (a) and (b). If you are having trouble, refer to those problems.