Does anyone know the answer to this?

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

Bradley hikes 12 miles in 3 hours. in relation to bradley’s hike, which statement describes the expression

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15