Answer:
See below.
Explanation:
So we have the system of equations:
![3x-2y=21 \text{ and } y=2x-4](https://img.qammunity.org/2021/formulas/mathematics/high-school/mrd98hahthhybpf9z4240vhcay2dtkjw1y.png)
The student took the following steps:
![3x-2(2x-4)=21\\3x-4x-8=21\\-x-8=21\\-x=29\\x=-29\\y=2(-29)-4=-58-4=-62](https://img.qammunity.org/2021/formulas/mathematics/high-school/d0b3x0ni3uwq5ojudiy7s91n3cfaqs6ttl.png)
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 plus 8, since -2 times -4 is positive 8. Fixing that mistake, we will have:
![3x-2(2x-4)=21\\3x-4x+8=21 \\-x+8=21\\-x=13\\x=-13\\y=2(-13)-4=-26-4=-30](https://img.qammunity.org/2021/formulas/mathematics/high-school/l1zn2zeme314mo0y8axr7j1yezqs06xfev.png)
Thus, the final answers should be (-13, -30).