The population density of a city is given by ​P(x,y)equalsnegative 20 x squared minus 30 y squared plus 600 x plus 480 y plus 170​, where x and y are miles from the southwest corner of the city limits and P is the number of people per square mile. Find the maximum population​ density, and specify where it occurs.
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Part 1
The maximum density is
  
enter your response here people per square mile at ​(x,y)equals
  
enter your response here.