In arithmetic, the aditive identity says that for some number a, a + 0 = 0 + a = 0. what would be an aditive
identity in matrix arithmetic?

X+ y = 5 ; x - y =3 solve using linear combination

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 you have 12 feet of string and you cut it into equal length of 5 inches each how much string will be left