Peter Linz Edition 4 Exercise 4.1 Question 13 (Page No. 109)

Question

If $L$ is a regular language, prove that $L_1 =$ {$uv : u ∈ L, |υ| = 2$} is also regular.

Answer 1

$u$ is $regular$ and

$v$ is of $length$ $2$ which is regular $($$because$ $of$ $finite$ $length$$)$

so $uv$ is also regular because regular language is closed under concatenation.