Final answer:
The perimeter of a square each side of which is (7 + 3x) units is given by the expression (4(7 + 3x)) units. This is because the perimeter is obtained by adding all four equal sides of the square.
Step-by-step explanation:
The question asks us to determine the perimeter of a square where each side is given by the expression (7 + 3x) units. Perimeter of a square is calculated by adding all the four sides together. Since a square has four equal sides, we can multiply the length of one side by 4 to find the perimeter. Therefore, the perimeter P is P = 4 × (7 + 3x) units. Simplified, this expression remains as is and does not need any additional math, thus the answer is (4(7 + 3x)) units.