This is a rather silly problem.
They gave the same equation four times . . . why?
. . Can we write: . and say "Solve the system of equations" ??
I don't think so!
If they had used three different variables, say, , it would make more sense.
Am I allowed to solve only one line? . . . . Yes!
I solved the first one and it gives three values for x: . . . . . Good!