If f(x) is the slope of a trail at a distance of x miles from the start of the trail, what does 7 f(x)dx 5 represent? The change in the elevation between x = 5 miles and x = 7 miles from the start of the trail. The elevation at x = 5 miles from the start of the trail. The elevation at x = 7 miles from the end of the trail. The elevation at x = 7 miles from the start of the trail. The change in the elevation between x = 5 miles and x = 7 miles from the end of the trail.