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.

Answer:
Option D is the correct option.
Step-by-step explanation:
The function a represents the cost of manufacturing of product A.
a(t) = 5t + 2
Similarly function b represents the cost of manufacturing of product B.
b(t) = 7t²- 2t + 4
Now we have to find an expression which represents the total cost of manufacturing of product A and B.
a(t) + b(t) = 5t + 2 + 7t² - 2t + 4
= 7t² + 3t + 6
Answer is function representing manufacturing cost of both the products A and B is Option D. a(t) + b(t) = (7t² + 3t + 6)