Me pls i really really need with this i'm so bad at math

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

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

Hi if you want to play a sports related kahoot go to kahoot.it and type in this code: 659344