Answer:
Option 'C i.e. Subtract to eliminate y' is the correct option.
Explanation:
Given the system of equations
-6x + 7y = -54
-7x + 7y = -56
The first step we need to do is to subtract to eliminate y, because 7y and -7y will cancel each other.
x + 0y = 2
x = 2
Therefore, we get x = 2 after we implemented the fist step to subtract to eliminate y.
Hence, option 'C i.e. Subtract to eliminate y' is the correct option.