What is the common difference of the arithmetic sequence. 25, 18, 11, 4,?

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Answer 1 · 2016-07-20T17:54:32

#d = -7#

The common difference is found by subtracting any two consecutive terms in an AP.

#d = T_4 - T_3 " "=" " T_3 - T_2" " = " "T_2 - T_1#

If you get the same answer, you know it is an AP.

If #d#, is positive, then the terms get bigger.

If #d#, is negative, then the terms get smaller.

In this case

#d = T_4 - T_3 " "=" " 4-11 = -7#

#T_3 - T_2 " " = " "11-18= -7#

#T_2 - T_1 " "= " " 18-25 = -7#