 
		        
		
		
		
		Find the sequences of differences as required.

From the lesson we know that the third-level difference is 6 times the coefficient of the cubic term ; we have

Using 
 as
the general form for a cubic sequence, create three equations using the first
three terms of the sequence and 2 for the a value.
as
the general form for a cubic sequence, create three equations using the first
three terms of the sequence and 2 for the a value.
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| Write as a matrix equation and solve using technology: 
 Substituting these values into the general form, we have the required equation 
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