#### Answer

$L1 $is the set of all strings of a’s and b’s that begins with an a and contain only that one a;
$ L2$ is the set of all strings of a’s and b’s that contain an even number of a’s.

#### Work Step by Step

$L1 $is the set of all strings of a’s and b’s that start with an a and contain only that one a;
$ L2$ is the set of all strings of a’s and b’s that contain an even number of a’s.
--$L_1L_2$ is the set of all strings of a’s and b’s that begins with an a and contain an odd number of $a’s$.
$L1∪L2$ is the set of all strings of a’s and b’s that contain an even number of a’s or that start with an a and contain only that one a.
($L1 ∪ L2$) ∗ is the set of all strings of a’s and b’s.
The reason is that a and b are both in $L1 ∪ L2$, and thus every string in a and b is in
$(L1 ∪ L2) *$.