4 years ago

Consider an arithmetic sequence where a1 = 5 and S9=297. find the common differece, d.

Mathematics

1 answer:

jenyasd209 [6]4 years ago

8 0

d = 7

The sum to n terms of an arithmetic sequence is

S $_{n}$ = n/2[ 2a₁ + (n - 1 )d]

here S₉ = 297

thus 9/2[ (2 × 5) + 8d] = 297

multiply both sides by 2 and divide by 9

10 + 8d = 66

subtract 10 from both sides

8d = 66 - 10 = 56

divide both sides by 8

d = $\frac{56}{8}$ = 7

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Answer:

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Let

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