Answer: The correct option is A.
Explanation:
The system of equations is,
When solving this system of linear equations with the elimination method, we can multiply the bottom equation by 3.
This step works because according to the multiplication property of equality,
If,
... (1)
Multiplied both side by m then,
..... (2)
Then (1) and (2) are equivalent equations.
So, by multiplication property of equality, the second equation can be multiply by 3.
Therefore, he correct option is A.