The annual yield per lemon tree is fairly constant at 390 pounds per tree when the number of trees per acre is 150 or fewer. For each additional tree over ​, the annual yield per tree for all trees on the acre decreases by 4 pounds due to overcrowding.

A. Express the yield per​ tree, Y, in​ pounds, as a function of the number of lemon trees per​ acre, x, where x is greater than 150.
B. Express the total yield for an​ acre, T, in​ pounds, as a function of the number of lemon trees per​ acre, x, where x is greater than 150.