Acar that originally cost $20,000 depreciates by 15% each year. in about how many years will the car be worth half its value? use the equation 10,000 = 20,000(8.5)^x to solve the problem. round your answer to the nearest dollar.

15 point ! ~ see if you know the answer to both you!

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.

If f(x) = 2x + 8 and g(x) = x4, what is (gº)?