Question

ME PUEDEN AYUDAR POR FIS......................................................

Answer 1

$\frac{ {7}^{n + 3} - {7}^{n + 2} + {7}^{n} }{ {7}^{n} } \\ \frac{ {7}^{n} \times {7}^{3} - {7}^{n} \times {7}^{2} + {7}^{n} }{ {7}^{n}} \\ \frac{ {7}^{n}( {7}^{3} - {7}^{2} + 1) }{ {7}^{n} } \\ 343 - 49 + 1 \\ 295$