Practice
simplify each expression by combining like terms.
1. 6x + 4x
2. – 5y + 2y
3. – 3m - 8(m + 1)
4. -81r - 2) + 6(r - 2) -
5. 9m - 7m + 13

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.

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2 acellus answer

Ef is a median of trapezoid abcd. the length of ab is 12, and the length of cd is 18. the length of bf is 4. what is the length of fc?