To evaluate an expression with variables:

1. Substitute the values for the variables.

2. Identify grouping symbols, beginning with the innermost symbols.

3. Determine and apply the rules of exponents to simplify.

4. Evaluate.

Evaluate the expression using x = –1 and y=3.
(6x4y3)

What is the value of the expression?
–162
–54
162
216

The weekly amount spent by a company for travel has an approximately normal distribution with mean = $550 and standard deviation = $40. a) what is the probability that the actual weekly expense will exceed $570 for more than 20 weeks during the next year? (note: one year = 52 weeks) b) what is the probability that actual weekly expenses exceed $580 for 10 or more, but 16 or fewer weeks during the next year?