Final answer:
The transition from Step 1 to Step 2 in the given equation utilizes the Distributive Property, which allows for multiplying a term outside a parenthesis by each term inside the parenthesis.
Step-by-step explanation:
The question asks which property of real numbers is used to justify the transition from Step 1 (5(x + 2) = -3x - 6) to Step 2 (5x + 10 = -3x - 6). The correct property is the Distributive Property, which states that a(b + c) = ab + ac. This property allows you to multiply a single term outside a parenthesis by each term inside the parenthesis. Therefore, applying the Distributive Property to 5(x + 2), we obtain 5x + 10, which aligns with Step 2.