Question

a soma dos 10 promeiros termos da PA [ 2,5,...]​

Answer 1

• $\sf{r=a2-a1}$

• $\sf{r=5-2}$

• $\sf{r=3}$

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• $\sf{a10=a1+9r}$

• $\sf{a10=2+9.(3)}$

• $\sf{a10=2+27}$

• $\sf{a10=29}$

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• $\sf{sn=n.(a1+an)/2}$

• $\sf{s10=10.(2+29)/2}$

• $\sf{s10=5.(31)}$

• $\sf{s10=155}$