The following is the description of a cost: Total fixed costs are $5,100 per month, and the variable cost per unit is $13.00 when production is under 1,000 units. The variable cost drops to $11.00 per unit after the first 1,000 units are produced. (a) Write the algebraic expression of the cost function. Cost Formula: Total Cost = $5100 + $13 x Quantity, for Quantity 1000 = 5100 + (11 x Quantity, for Quantity >1000