Question

va rog urgent! dau coroana!

Answer 1

$a=3^{n}+3^{n+1}+3^{n+2}+3^{n+3}\\\\Scoatem\ factor\ comun\ 3^{n}\\\\a=3^{n}*(1+3^{1}+3^{2}+3^{3})\\\\a=3^{n}*(1+3+9+27)=3^{n}*40\ =>\ a\ este\ multiplu\ de\ 40$

Answer 2

Sper sa te ajute! Succes!