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| Question 180879This question is from textbook College Algebra a Graphing Approach
 :  Rental Demand:A real estate office handles an apartment complex with 50 units. When the rent per unit is $580 per month, all 50 units are occupied. However, when the rent is $625 per month, the average number of occupied units drops to 47. Assume that the relationship between the monthly rent p and the demand x is linear.
 a. Write the equation of the line giving the demand x in terms of the rent p.
 b. Use a graphing utility to graph the demand equation and use the trace feature to estimate the number of units occupied when the reant is $655. Verify your answer algebraically.
 c. Use teh demand equation to predict the number of units occupied when the rent is lowered to $595. Verify your answer graphically.
 Thanks - I'm so frustrated and have been stuck on word problems for 2 weeks. - Thanks 
This question is from textbook College Algebra a Graphing Approach
 
 Answer by ankor@dixie-net.com(22740)
      (Show Source): 
You can put this solution on YOUR website! A real estate office handles an apartment complex with 50 units. When the rent per unit is $580 per month, all 50 units are occupied. However, when the rent
 is $625 per month, the average number of occupied units drops to 47.
 Assume that the relationship between the monthly rent p and the demand x is linear.
 :
 a. Write the equation of the line giving the demand x in terms of the rent p.
 :
 Using the slope formula: m =
  find the slope Assign the given values as follows
 x1 = 580; y1 = 50
 x2 = 625; y2 = 47
 m =
  =  =  Write the equation using the point/slope formula y - y1 = m(x - x1)
 y - 50 =
  (x - 580) y - 50 =
  (x - 580) y =
  x + 38.67 + 50 y =
  x + 88.67 The way they have written it, demand (d) dependent on price (p) it would be
 d =
  p + 88.67 :
 :
 b. Use a graphing utility to graph the demand equation and use the trace feature to estimate the number of units occupied when the rent is $655. Verify your answer algebraically.
 :
 Substitute 655 for p in the above equation
 d =
  (655) + 88.67 d = -43.67 + 88.67
 d = 45 units rented at $655
 :
 On a TI83, it would look something like this:
 (Xmin=-100, Xmax=800; Ymin=-20, Ymax=100)
 
  :
 :
 c. Use the demand equation to predict the number of units occupied when the rent is lowered to $595. Verify your answer graphically.
 :
 Substitute 595 for p in the above equation in the same way
 d =
  (595) + 88.67 d = -39.67 + 88.67
 d = 49 units rented at $595, verify on the same graph
 :
 :
 they should not have assigned the demand as x. x is usually the independent
 variable and here, the demand is the dependent variable. Causes confusion.
 :
 Hopefully, this has relieved some of your frustration, and you can enjoy the rest of this blessed Sunday!  Carl
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