An 80% confidence interval is found to be (12, 20). What is the margin of error?
A. 4.
B. 3.2
C. 6.4
D. 8

Factor the monomial completely 42a3b3

What are the solutions of the system? solve by graphing. y = x^2 + 3x + 2 y = 2x + 2

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers