Let C present amount of change
The expression is C = 50 - d
1)Calculate the product:
21a + 10a - 3a
2)Collect like terms:
28a
Answer:
28a
To get the answer you have to fill in the 14 for r because that is the radius. Then multiply 14 by it self to get 196 then multiply that by pie to get your answer of 615.75216.
So the answer is 615.75216