System of equations is the perfect app to practice the resolution of them.
You can choose four options:
-Methods. Choose one of the three methods (igualation, subtitution or reduction) and solve the system that the app give you.
-Solve. A random system of equation to solve.
-Problems. Many word problems to solve with systems.
-Autosolve. Write your system and get the solution.
All the system have the solution, that will appear when you press the button.