Design of algorithm course

What is the basic operation and how to solve the recurrence relation in steps step$-$by$-$step please. I don$$t understand this problem can you explain it

$($Home Work$).$ Let $A[0...n-1]$ be an array of $n$ integers and $x$ an integer. Derive a divide$-$and$-$ conquer algorithm $($two equal divisions$)$ to find the frequency of $x$ in $A,$ i$.$e$.,$ the number of times $x$ appears in A $.$ What is the time complexity of your algorithm?