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Determine the sum of the first thirty terms of the sequence 537, 524, 511, . . .​

Sagot :

Answer:

[tex]S_{n}=10,455[/tex]

Step-by-step explanation:

find [tex]a_{30}[/tex]:

[tex]a_{n}=a_{1}+(n-1)d\\a_{30}=537+(30-1)(-13)\\a_{30}=537+(29)(-13)\\a_{30}=537+(-377)\\a_{30}= 160[/tex]

Solution:

[tex]S_{n}=\frac{n}{2} (a_{1}+a_{n})\\S_{n}=\frac{30}{2} (537+160)\\S_{n}=\frac{30}{2} (697)\\S_{n}=15(697)\\S_{n}=10,455[/tex]