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# Nth term of 25 21 17 13 9 5?

To find the nth term you need to find the constant difference This is the term to term rule In this case 21-25=-4, 17-21=-4, etc So our constant difference is -4. This becomes the coefficient (number next to) n in the nth term The next step is to find out what we need to add to this to reach our first term As the nth term in linear sequences is an+c, we know a=-4 Substitute n=1 so we have -4 * 1 +c= 25 We rearrange to find c=29 This gives us an nth term of -4n+29 and this can be checked against your other values Hope this was helpful!

Lauren Holland
·

2.3k students helped

Ans: -4n+29 Explanation: The difference down the sequence is -4. Then the position number times the difference is worked out. Eg 25 is position 1 so 1x-4=-4. 21 is position 2 so 2x-4=-8 and so on for the rest of the sequence. Then work out the difference from the new number to the original number. Eg. -4 to 25=29. -8 to 21=29 -12 to 17=29 So the answer is -4n+29

Durga Jeyasingham
·

225 students helped

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