Answer:
Area = (8 + 2x)² mi²
Explanation:
Length of the side of a park = 8 mi
Width of the road around the park = x mi
Length of one side of the park with the road = (8 + 2x) mi
Area of the park with road = (side)²
= (8 + 2x)²
Therefore, combined area of the park and road is (8 + 2x)² square miles.