The equation \( 5x + 3 = x \cdot 5 + 3 \) is a test case for the Commutative Property of Multiplication.
The Commutative Property states that changing the order of the factors does not change the product. In this case, \( 5x \) can be rewritten as \( x \cdot 5 \), demonstrating that the order of multiplication does not affect the outcome. Therefore, by substituting \( 1 \) into the equation, you are showing that both sides are equivalent using this property.