Explicati-mi cum se rezolva urmatoarele exercitii:
[tex]2^{20} + 2^{30} + 2^{42} + 2^{51} + 2^{6} =
 
2^{2} + 2^{3} + 2^{4} ...+ 2^{20} =
 
1*2*3*4*...*50 =
 
8^{n} +8^{n+1} =18 * 2^{2003}[/tex]