The y intercept is going to be 10x
Yes, because there are zeros after the 8. 0.8 miles is equal to 0.80 miles, which is larger than 0.69 miles
The first reaction represented is a decomposition reaction due to the fact the bonded pair are being split apart.
The second equation is a single displacement because the B and C have switched places, which is the only change making it a single displacement. If there had been another bond and A had also moved, it would be double.
The answer is 78 feet of fencing. This is because you need to find the perimeter of the yard. To find the perimeter of the yard, you add the sides together, so 21+21+18+18 = 78.