Answer:
8 units
Step-by-step explanation:
Points (2, 5) and (10, 5) have the same y-coordinate, so lie on the horizontal line y = 5. The distance between the points is the difference of their x-coordinates:
10 -2 = 8
The points are 8 units apart.
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If you plot the points on a graph, you can count the grid squares between them.