[tex]a)~A=6^{n}+3^{n}+2^{n}+1[/tex]
[tex]A=(2*3)^{n}+3^{n}+2^{n}+1[/tex]
[tex]A=2^{n}*3^{n}+1*3^{n}+2^{n}+1[/tex]
[tex]A=3^{n}(2^{n}+1)+1*(2^{n}+1)[/tex]
[tex]A=(2^{n}+1)(3^{n}+1)[/tex]
[tex]=>A~este~compus[/tex]
[tex]b)~B=15^{n}+5^{n+1}+3^{n}+5[/tex]
[tex]B=(3*5)^{n}+5^{n}*5+3^{n}+5[/tex]
[tex]B=3^{n}*5^{n}+5^{n}*5+3^{n}+5[/tex]
[tex]B=3^{n}*5^{n}+3^{n}*1+5*5^{n}+5*1[/tex]
[tex]B=3^{n}(5^{n}+1)+5(5^{n}+1)[/tex]
[tex]B=(5^{n}+1)(3^{n}+5)[/tex]
[tex]=>B~este~compus[/tex]