Error Analysis

1)

The error in this equation is that the slope goes up by 2, not 10, so the equation should read y=2x+9

2)

The error with this system of equations is that the student should have plugged the solution into both  equations, not just one, to check and see if the point works for both problems.

3)

For the first inequality, the error is that the line should have been dotted, since the actual equation isn't included in the solution. For the second inequality, the solutions should have been shaded above the line, since the equation says "greater than or equal to".

4)

For the first inequality, the line should be dotted, again, since the actual equation isn't included in the solution. For the second inequality, the solutions should be shaded below the line since the equation reads "less than or equal too".