Solve the quadratic equation by completing the square 3x^2 -6x-4=0

Which of the following is the result of expanding the series

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.

The measurement of one angle of a right triangle is 42° what is the measurement of the third angle? (there is no picture)