A. y = - (x – 2)2 B. y = -(x - 2)2 C. y = (x + 2)? D. y = -(x + 2)² 7. A. y = -4(x + 2)² + 1 B. y = -4(x – 2)² – 1 C. y = 4(x – 2)² +1 D. y = 4(x – 2)² – 1 8.

Find an example of a quadratic function in the field of your interest. Draw its picture in the coordinate plane. Find its vertex, x-intercept(s), y-intercept, and max or min value and explain what they represent in your problem

iPhone Sales The table lists the number of iPhones sold in millions in the first 5 years on the market. Find a quadratic function f that models the data. Year 1 2 3| 4 5 Units sold 1 20 | 50 | 100| 180| Source: Business Insider.

The graph shows a quadratic function of the form R(t) = at2+bt+c, which represents the yearly revenue for a company, where R(t) is the revenue in year t.   a. Is the value of a positive, negative, or zero?  Explain. b. Write an expression in terms of a and b that represents the year t when the company had the least revenue. c. The company made the same yearly revenues in 2008 and 2018.  Estimate the year in which the company had the least revenue. d. Assume that the model is still valid today.  Are the yearly revenues currently increasing, decreasing, or constant?  Explain.