Find the difference x+1/x-1-x-8/x-1

#12 find the value of x. #13 find the value of the variable.

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

Mila's dog weighs 4 pounds more than 8 times the weight of keiko's dog. which expression could be used to fine te weight of mila's dog?