The marketing research department of a computer company used a large city to test market the firm's new laptop. the department found the relationship between price p (dollars per unit) and the demand x (units per week) was given approximately by the following equation. pequals1836 minus 0.17 x squared 0less thanxless than75 so, weekly revenue can be approximated by the following equation. upper r (x )equalsxpequals1836 x minus 0.17 x cubed 0less thanxless than75 use this information to answer parts (a) and (b).