What is the solution to the following system? 3x + 3y + 3z = -12
5x + 2y + 2z = -17
2x-4y - z = -20

To solve the systems, you have to use one of the equations to remove one of the variables from the rest of the equations. In this example, I use the third equation to get rid of the z in the other 2 equations. Then you can just use elimination to find one of the variables, and substitute values in the equations to find the rest.