Answer:
Given -2x + 7x + 8, the correct expression is 5x + 8.
Step-by-step explanation:
The student didn´t notice that 8 was not follow by x, and try to apply common factor. But we can´t do that. The correct form to solve this expression is -2x + 7x + 8 = (-2 + 7)x + 8 = 5x +8.