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How many terms are in the arithmetic sequence shown below?15, 7, -1, -9...,-225

Kristi Hammond

in Mathematics

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Kaitlin Dean on March 17, 2019

We know give you can write an Arithmetic progression as a general rule:an = a1 + d(n−1)wherea1 = the first termd =the "difference" between termsin this problem1=15 a2=7 a3=-1 a4=-9 ..... an=-225d=a2-a1=d 7-15-----> d=-8an = a1 + d(n−1)foran=-225d=-8a1=15find n-225=15+(-8)*(n-1)--> (n-1)=[-225-15]/-8----> n-1=30---> n=30+1---> n=31the response is31


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