Answer: -s + 5x
Explanation:
 We cannot solve this since it is not an equation. However, we can simplify this expression by combining like terms.
Given:
 7s + 5x - 8s
Combing like terms, 7s - 8s:
7s - 8s is -1s, we do not write the one so it simplifies to -s.
 -s + 5x