Răspuns:
[tex] {2}^{n} \times {5}^{n} \times 5 - {2}^{n} \times 2 \times {5}^{n} = {10}^{n} \times 5 - {10}^{n} \times 2 = {10}^{n} (5 - 2) = {10}^{n} \times 3[/tex]
la al doilea exercițiu
[tex] {6}^{n} \times 3 + {6}^{n} \times 4 = {6}^{n} \times 7[/tex]