I need help with the following questions and I also need to see the steps and formulas included for the answer. No Excel Solutions!!

Local Co. has sales of $ 10.4 million and cost of sales of $ 6.2 million. Its selling, general and administrative expenses are $ 460,000 and its research and development is $ 1.2 million. It has annual depreciation charges of $ 1.2 million and a tax rate of 35%. Local's gross margin is 40.38%,

its operating margin is 12.88%, and its net profit margin is 8.38%. If Local Co. had interest expense of $ 900,000, how would that affect each of its margins?