Looking at the linear system below, which variable would be easiest to use substitution? X + y - z = -2

2x + 3y - z = -3

X - Y = Z

A. Z
B. X
C. Y

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500