John spent 2/3 of his savings on a new Bluetooth speaker. the speaker cost $80. how much did John have in savings before he bought the speaker?

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.

Write an equation of the line that passes through 9,2 and is parallel to the line y=5/3x+9

Solve each quadratic equation by factoring and using the zero product property. x^2 - 8x + 30 = 3x