Which equation can be solved by using this system of equations?

If you observe the two given equations, the left hand side of both equation is the same and is equal to y.

Since the left hand side of two equations is the same, we can conclude that the right hand side of two equations must also be the same. 

So, setting them right hand sides of both equations equal to each other and solving for x, we can find the solution to the simultaneous equations.

Therefore, the correct answer is option B