Can someone help me with these

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

Which basic geometric term has no width, no length, and no thickness? line b. point c. angle d. plane

Write the equation for the parabola that has x− intercepts (−2,0) and (4,0) and y− intercept (0,4).