Answer:
(A)
Step-by-step explanation:
That rule isn't used in the elimination methods for systems of equations, but, rather, it is used in substitution methods. The other rules are used in elimination.
Please tell me if I got it wrong. I really hope it is correct.
A. Add the left side of equation 2 to the left side of equation 1.
B. Multiply equation 2 by 3. Then subtract the result from equation 1.
C. Add equation 2 to equation 1.