Question

rapid va rog apasati pe poza!​

Answer 1

 

$\displaystyle\bf\\S=3\cdot2^n+2^{n+1}+5\cdot2^{n+1}+2^{n+3}\\\\S=3\cdot2^n+6\cdot2^{n+1}+2^{n+3}\\\\S=3\cdot2^n+6\cdot2^n\cdot2+2^n\cdot2^3\\\\S=2^n(3+6\cdot2+2^3)\\\\S=2^n(3+12+8)\\\\S=2^n\cdot23\\\\S~\vdots~23$