Determine if the sequence below is arithmetic or geometric and determine the common difference / ratio in simplest form. 3,12,21

Step-by-step explanation:  5 18 9 55

3             + 9   = 12

12           + 9   = 21

21           + 9   = 30

30

arithmetic or geometric

common difference / ratio    the difference is 9

2 x^2 -3x+p

sum of roots = 3/2

let other root be x

3+ x = 3/2

x= 3/2 - 3 = -3/2

product of roots = p/2

3× -3/2 = p/2

-9 = p

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i think it is 18

step-by-step explanation: