Verdadero o Falso:
A) El elemento neutro para la multiplicación de polinomios es el polinomio nulo.
B) La suma de dos polinomios del mismo grado siempre tiene el mismo grado de los sumandos.
C) El elemento neutro para la suma de polinomios es el polinomio nulo.
D) Si dos polinomios tienen el mismo grado, su producto tambien lo tiene.

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.