In this exercise, you will practice ‘undoing’ operations.
The expression
$\,2x + 1\,$
represents the sequence of operations:
start with a number
$\,x\,$, multiply by $\,2\,$, then add $\,1\,$.
To ‘undo’ these operations and get back to
$\,x\,$, we must apply the sequence:
subtract
$\,1\,$, then divide by $\,2\,$.
Start with $\,x\,$ and follow the arrows in the diagram below.
This shows you doing something, and then undoing it, to return to $\,x\,$!
$x$  $\overset{\text{multiply by 2}}{\rightarrow}$  $2x$  $\overset{\text{add 1}}{\rightarrow}$  $2x + 1$ 
$\,\downarrow\,$  
$x$  $\overset{\text{divide by 2}}{\leftarrow}$  $2x$  $\overset{\text{subtract 1}}{\leftarrow}$  $2x + 1$ 
Remember some key ideas:
CONCEPT QUESTIONS EXERCISE:
On this exercise, you will not key in your answer.However, you can check to see if your answer is correct. 
PROBLEM TYPES:
