Question

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I need help nmuber 26,27
the key 27 is: 20.100 thank you in advance

Answer 1

Hi Salina,

Fir 26th question the series formula is \[t _{n}=t _{n-1}+n\]

Answer 2

Here you go explanation \[t _{1}=1, t _{2}=t _{1}+2=3, t _{3}=t _{2}+3=6, t _{4}=t _{3}+4=10 like that\]