Solution
For this case we have the following system of equations:
-3x -3y= 39
-6x +3y =-12
Then the correct first step would be:
Add to eliminate y
For the second part we have:
6x -8y= -94
-x +8y= 49
Then the correct first step would be:
Add to eliminate y
For the third case we have:
10x+10y =-79
10x -7y = 15
The correct first step is:
Subtract to eliminate x
For the last case we have:
-3x +2y = -15
-3x -6y =9
The correct first step is:
Subtract to eliminate x