Answer:
Final answer is [tex]S_n=565.5[/tex].
Step-by-step explanation:
Given that [tex]a_1=12[/tex], [tex]a_n=75[/tex], and [tex]n=13[/tex].
Using those values, we need to find the value of [tex]S_n[/tex].
Plug these values into sum formula :
[tex]S_n=\frac{n}{2}\left(a_1+a_n\right)[/tex]
[tex]S_n=\frac{13}{2}\left(12+75\right)[/tex]
[tex]S_n=\frac{13}{2}\left(87\right)[/tex]
[tex]S_n=\frac{1}{2}\left(1131\right)[/tex]
[tex]S_n=565.5[/tex]
Hence final answer is [tex]S_n=565.5[/tex].
