10.6.37-BE Question Help A manufacturer of handcrafted wine racks has determined that the cost to produce x units per month is given by C=0.4x2 + 10,000. How fast is the cost per month changing when production is changing at the rate of 18 units per month and the production level is 70 units? Costs are at the rate of $ per month at this production level. (Round to the nearest dollar as needed.) Enter your answer in the answer box and then click Check Answer. ? All parts showing Clear All Check Answer 11:28 PM