Which of the following is not a true statement about solving two-step equations?
a. two-step equations require the addition property of equality to solve.
b. two-step equations require the multiplication property of equality to solve.
c. two-step equations require all numbers to be whole numbers in order to solve.
d. two-step equations can be solved even with coefficients that are fractions.

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.