Răspuns :
Explicație pas cu pas:
a)
[tex]\bf A=2^0 + 2^1 +2^2[/tex]
[tex]\bf A=1 + 2 +4[/tex]
[tex]\purple{\boxed{~\bf A=7\implies A~\vdots~7~}}[/tex]
b)
[tex]\bf A=2^0 + 2^1 +2^2 +2^{3}+2^{4}+2^{5} + ....+2^{2003}[/tex]
[tex]\bf A=\Big(2^0 + 2^1 +2^2\Big)+\Big(2^{3}+2^4+2^{5}\Big)+ ...+\Big(2^{2001}+2^{2002}+2^{2003}\Big)[/tex]
[tex]A=\Big(1+ 2 +4\Big)+2^{3}\cdot\Big(2^{3-3}+2^{4-3}+2^{5-3}\Big)+ ...+2^{2001}\cdot\Big(2^{2001-2001}+2^{2002-2001}+2^{2003-2001}\Big)[/tex]
[tex]\bf A=7+2^{3}\cdot\Big(2^{0}+2^1 +2^2\Big)+ ...+2^{2001}\cdot\Big(2^{0}+2^1 +2^2\Big)[/tex]
[tex]\bf A=7+2^{3}\cdot\Big(1+ 2 +4\Big)+ ...+2^{2001}\cdot\Big(1+ 2 +4\Big)[/tex]
[tex]\bf A=7+2^{3}\cdot 7+ ...+2^{2001}\cdot 7[/tex]
[tex]\red{\boxed{~\bf A=7\cdot\Big(2^{0}+2^{3}+2^{6}+... +2^{2001}\Big)~~\vdots~~7~}}[/tex]
[tex]==pav38==[/tex]
