(05.03)
 What is the rate of change and initial value for the linear relation that includes the points shown in the table?
 x y
 1 20
 3 10
 5 0
 7 -10
 a. initial value:20, rate of change: 10
 b. initial value:30, rate of change: 10
 c. initial value:25, rate of change: -5
 d. initial value: 20, rate of change: -10