What is the 21st term of the sequence with a1 = -7 and d = 3?

The function a represents the cost of manufacturing product a, in hundreds of dollars, and the function b represents the cost of manufacturing product b, in hundreds of dollars. a(t) = 5t + 2 b(t) = 7t - 2t +4 find the expression that describes the total cost of manufacturing both products, a(t) + b(t). a. 7t^2 - 7t + 2 b. 7t^2 + 3 +6 c. 7t^2 + 7t - 6 d. 7t^2 - 3t + 6

Determine if the function below is continuous. a. continuous b. not continuous, 1 hole c. not continuous, > 2 holes d. not continuous, 2 holes

Tan198=asin164=? how to solve this? ?