34 \\ 2(x + 7) < 40 \\ \\ 2x + 14 > 34 \\ 2x + 14 < 40 \\ \\ 2x > 34 - 14 \\ 2x < 40 - 14 \\ \\ 2x > 20 \: \: \: | \div 2 \\ 2x < 26 \: \: \: | \div 2\\ \\ x > 10 \\ x < 13" alt="2(x + 7) > 34 \\ 2(x + 7) < 40 \\ \\ 2x + 14 > 34 \\ 2x + 14 < 40 \\ \\ 2x > 34 - 14 \\ 2x < 40 - 14 \\ \\ 2x > 20 \: \: \: | \div 2 \\ 2x < 26 \: \: \: | \div 2\\ \\ x > 10 \\ x < 13" align="absmiddle" class="latex-formula">
Ответ: 11 см или 12 см