Answer
a.) { x $\mid$ 2 $\lt$ x $\lt$ 7}
b.) (2,7)
Work Step by Step
a.) The line { x $\mid$ 2 $\lt$ x $\lt$ 7} states that x can be any variable that is greater than the whole number 2, but less than the whole number 7. This means that the numbers (3, 4, 5, 6) are between the bounds.
b.) The notation definition (a,b) is labeled with the set description { x $\mid$ a $\lt$ x $\lt$ b}. The set description is particularly similar to part a of this question { x $\mid$ 2 $\lt$ x $\lt$ 7}. We can use this set description to be notated as (2,7).