Math 118

Chapter 6

Practice test

You have a 30 point test on Thursday, October 16.  It will look a lot like this:

            No graphing calculators or cell phones. 

            Show your work.  Show your matrix at each step, and tell what you do to get to the next step.

1.         (5 points)            Write the “augmented matrix” corresponding to the following linear system:

                        2x        +y         + z       = 9

                        3x        + y       + z       = 12

                        2x         -y         + z       = 5 

2.         (15 points) Use any method to solve the system.  Show your work. Make sure it is neat enough and well organized so that I can understand what you did.  No work, no credit.  Do the work on the scrap paper and write the final form in the space below:

x = _____                    y = _____                    z = _____

3.     (5 points)  What is the name of the method you used?  

4.         (5 points)          Show how to check your solution to make sure it is correct (or, if your solution is incorrect, how the check shows it is incorrect).

To find the answers, look at the December line of the calendar on the course home page.