Respuesta :

luana
[tex]2S=n(a+k)\ \ \ |Omit\ the\ bracket\\\\ 2S=na+nk\ \ \ \ |Subtract\ "na"\ from\ each\ side\\\\ 2S-na=nk\ \ \ \ |Divide\ by\ n\\\\ \frac{2S-na}{n}=k\\\\Solution\ is\ k=\frac{2S-na}{n}.[/tex]