Answer:
C (and D)
Explanation:
The multiplication property of equality says the value of the variable is unchanged when both sides of the equation are multiplied by the same value.
In A, no property of equality is involved. The two equations are for different lines.
In B, the subtraction property of equality is used to subtract 9 from both sides of the equation.
In C, the multiplication property of equality is used to multiply both sides of the equation by 3.
In D, the division property of equality is used to divide both sides of the equation by 5. (This is equivalent to using the multiplication property to multiply both sides of the equation by 1/5.)
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If you're allowed one choice, the best selection is C. If multiple choices are allowed, both C and D are correct answers.