5. The ratio of a rectangle's width to its length is 2:5. If its perimeter is 84 feet, find its width, in feet.
6. Renting a private party room in a restaurant can be modeled as a linear function. If the cost of a party of 8 is $270, and the cost of a party of 10 is $320, find the cost, in dollars, of a party of 18.
7. Darren receives $9 an hour for his afterschool job, but gets paid 11/2 times this salary for each hour he works on a weekend. If he worked 18 hours one week and received $189, how many of these hours did he work on weekends?
8. If p > 0, and the distance between the points (4, -1) and (-2, p) is 10, find p.
9. If a - b = 8 and ab = 10, then a2 + b2 =
The pyramid above has a square base of length 10 cm and a height of 12 cm. Determine the total surface area of all five faces, in square centimeters.