4. Mr. Long selected a radio for his son's birthday present. The regular price of the radio was $80, but the radio was on sale at a 25% discount. Mr. Long also had to pay an 8% sales tax on the sale price. How
much did Mr. Long pay for the radio?
F $60.00
G $64.80
H $86.60
J $65.80

How do you solving the solution of each system using elimination?

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)

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.