Question

30 e si f
. va roggggg mult !!!​

Answer 1

Explicație pas cu pas:

e)

$\frac{1}{7} < \frac{3}{n - 2} < \frac{5}{4}$

$\frac{7}{1} > \frac{n - 2}{3} > \frac{4}{5} \iff \frac{105}{15} > \frac{5(n - 2)}{15} > \frac{12}{15} \\ 12 < 5(n - 2) < 105 \iff 12 < 5n - 10 < 105 \\ 22 < 5n < 115 \implies \frac{22}{5} < n < 23$

=> n ∈ {5, 6, 7, ..., 20, 21, 22}

f)

$\frac{7}{10} < \frac{2n + 1}{20} < \frac{6}{5} \iff \frac{14}{20} < \frac{2n + 1}{20} < \frac{24}{20} \\ 14 < 2n + 1 < 24 \iff 13 < 2n < 23 \\ \frac{13}{2} < n < \frac{23}{2} \implies 6 \frac{1}{2} < n < 12 \frac{1}{2}$

=> n ∈ {7, 8, 9, 10, 11, 12}