4 MT&A uses the function f(x) - 475 - 15x. to depreciate smart phones
where f represents the value of a smart phone and represents the
number of months since its purchase
Part A Find - and explain what it represents in this situation,
f(x) 495-15
Part B: When will the depreciated value of a smart phone be less than
$1002
Part C: What does x represent in f(x) = 308 What is the value of x?
Part D: Graph f(x) and f(x) on the same coordinate plane below
y

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.