Answer:
 is the slope, and the percent grade of this is 12.5%.
 is the slope, and the percent grade of this is 12.5%.
Explanation:
The slope of any linear equation is always rise over run.
Since we rise 8 feet for every 64 feet travelled horizontally, our fraction is
 which simplifies to
 which simplifies to 
 , so
, so 
 is the slope.
 is the slope.
To find the percent grade, we find the decimal version of 
 and multiply by 100.
 and multiply by 100.

Hope this helped!