1. The problem asks to identify the property illustrated by the statement: "If $x = y$, then $3x = 3y$." 2. This statement shows that if two quantities are equal, then multiplying both sides of the equation by the same number keeps the equality true. 3. The property used here is called the Multiplication Property of Equality. 4. The Multiplication Property of Equality states: If $a = b$, then $ca = cb$ for any number $c$. 5. In this problem, $a = x$, $b = y$, and $c = 3$, so multiplying both sides by 3 preserves equality. 6. Therefore, the correct property is the Multiplication Property of Equality. Final answer: Multiplication Property Of Equality