Answer:
See below.
Step-by-step explanation:
So we have the system of equations:

The student took the following steps:

The student's mistake is in step 2. He/she distributed incorrectly. You are supposed to distribute the -2 to both terms, so it should be -4x <em>plus</em> 8, since -2 times -4 is <em>positive </em>8. Fixing that mistake, we will have:

Thus, the final answers should be (-13, -30).