3) A model for advertising response is given by N(a) = 6010 + 400 In a where N(a) is the number of units solid and a is the amount spasit on advertising In thousands of dollars. a) Interpret the meaning of N(3) = 6439 in context of the problem. Use complete sentences. bJ Find N(2), then interpret the meaning of N'(2) in context of the problem. Use complete sentences