Answer:
-600
Explanation:
Jackson's initial score was 300, then his later score became -300, so you know that he had to lose points.
-300=300+x
** x represents the point change
Then just solve the equation by getting x by itself. You do this by subtracting 300 from both sides:
-300=300+x
-300 -300 = -300-300+x
-600 = x