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1.

A manufacturer of aluminum doors currently is able to sell 400 doors per week at a price of $75 each. If the price were lowered to $65 each, an additional 70 doors per week could be sold. Estimate the current elasticity of demand for the doors, and also estimate the current value of the manufacturer's marginal-revenue function. The elasticity of demand for the doors is approximately ]. (Type an integer or a decimal. Do not round until the final answer. Then round to the nearest hundredth as needed.)Use implicit differentiation to find dy / dx. 2xy - 9x+ y= -7 dy dx