Ответ:

[tex]\displaystyle \frac{10 \times {2}^{n - 1} - 5 \times {2}^{n} }{6 \times {2}^{n + 1} + 3 \times {2}^{n} } = \frac{10 \times {2}^{n} \times \frac{1}{2} - 5 \times {2}^{n} }{6 \times {2}^{n} \times 2 + 3 \times {2}^{n} } = \frac{5 \times {2}^{n } - 5 \times {2}^{n} }{12 \times {2}^{n} + 3 \times {2}^{n} } = \frac{0}{15 \times {2}^{n} } = 0[/tex]