Rate of change is not constant
First column and second column
Rate of chage = (76-38)/(4-2) = 38/2 = 19
second and third
Rate of chnage = (133-76)/ (7-4)
= 57/3 = 19
Third and fourth
Rate of change = (171-133)/(9-7)
= 38/2 = 19
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