Hello!
The answers are:
- A and B have different solutions.
- System C simplifies to 2x - 3y = 4 and 4x - y = 18 by dividing the second equation by three.
- Systems A and C have the same solution.
Why?
Let's solve each equation system in order to be able to choose the correct statements:
System A

For the second equation we have:

Then, substituting y into the first equation:

Then, substituting x into the second equation:

So, for the system A, we have:
x= 5
y= 2
System B

Substituting y into the first equation we have:

Substituting x into the second equation, we have:

So, for the system B, we have:
x= -1
y= -2
System C

Dividing the second equation by three, we have:

Substituting y into the first equation, we have:

Substituting x into the second equation, we have:

So, for the system C, we have:
x=5
y=2
Conclusions
System A and B have different solutions, since:
System A: X=5 and Y=2
System B: X=-1 and Y=-2
System C simplifies to 2x - 3y = 4 and 4x - y = 18 by dividing the second equation by three, since:
We did the simplification when we were solving the System C:
3(4x-y-18)=12x-3y-54=0
12x-3y=54
System A and C have the same solution, since:
System A: X=5 and Y=2
System C: X=5 and Y=2
Have a nice day!