Final answer:
The correct expression is (8x + 3)^2, which is obtained by first determining the sum of 8 times x and 3 and then squaring that entire sum.
Step-by-step explanation:
The expression described by the verbal description "the square of the sum of 8 times x and 3" is mathematically represented by option a, which is (8x + 3)^2. To understand how to construct this expression, we first construct the sum of 8 times x and 3, which is 8x + 3. We then take the square of this entire sum, which means we raise the sum to the power of 2. So, the expression (8x + 3)^2 means that everything inside the parentheses is multiplied by itself.