Răspuns:
[tex] {7}^{x} + {7}^{x + 1} = {2}^{3} \times {7}^{2016} \\ [/tex]
[tex] {7}^{x} \times (1 + 7) = 8 \times {7}^{2016} [/tex]
[tex]8 \times {7}^{x} = 8 \times {7}^{2016} [/tex]
[tex] {7}^{x} = {7}^{2016} [/tex]
[tex]x = 2016[/tex]
sper ca te am ajutat :)
