Answer
The student did not realize that once you have a common denominator, the denominator stays the same for the answer. Instead, the student added the denominator, getting $2x+6$.
Work Step by Step
The student did not realize that once you have a common denominator, the denominator stays the same for the answer. Instead, the student added the denominator, getting $2x+6$. The denominator should have remained as $x+3$, making the final answer $\frac{5}{x+3}$.
