Consider this scenario: The profit of a company decreased steadily over a ten-year span. The profit depends on the number of units sold. The following ordered pairs show the number of units sold x in hundreds and the profit P in thousands of dollars over the ten-year span in the form (x, P(x)) for specific recorded years. (46, 1640), (48, 1590), (50, 1545), (52, 1580), (54, 1535)

Required:
a. Use linear regression to determine a function P(x).
b. Find the x-intercept. (Round the coordinates to two decimal places.)