Watch the 3 videos and you must get a 70 or higher on the Khan academy practices for credit.
Khan Academy Practice: Checking the solution to a system
Khan Academy Practice: Solving a system of equations by graphing
You can use desmos.com graphing calculator to find solutions by graphing. You do not have to do the khan academy graphs only enter the x and y, but feel free to if you want.
Khan Academy Practice: Creating a system in context