1. The problem is to find the value of $a$ in the expression or equation given (though the exact equation is not specified). 2. To solve for $a$, we need the equation or expression involving $a$. Since it is not provided, please provide the full equation or context. 3. Generally, to find $a$, isolate $a$ on one side of the equation using algebraic operations such as addition, subtraction, multiplication, division, or factoring. 4. Once isolated, simplify the expression to get the value of $a$. Please provide the full equation or expression to proceed with solving for $a$.