Explicație pas cu pas:
1)
[tex]( \frac{3}{5} + \frac{1}{2} \times \frac{4}{7}) \div \frac{31}{7} - \frac{1}{10} \\ \\ (\frac{3}{5} + \frac{2}{7}) \div \frac{31}{7} - \frac{1}{10} \\ \\ \frac{31}{35} \times \frac{7}{31} - \frac{1}{10} \\ \\ \frac{1}{5} - \frac{1}{10} \\ \\ \frac{2 - 1}{10} = \frac{1}{10} [/tex]
2)
[tex](2.4 - 0.1 \times (6.25 - (0.65 + 0.12 \div 0.2)) \div 2) \times {10}^{2} \\ \\ (2.4 - 0.1 \times (6.25 - (0.65 + 0.6)) \div 2) \times 100 \\ \\ (2.4 - 0.1 \times (6.25 - 1.25) \div 2) \times 100 \\ \\ (2.4 - 0.1 \times 5 \div 2) \times 100 \\ \\ (2.4 - 0.25) \times 100 \\ \\ 2.15 \times 100 \\ \\ 215[/tex]
3)
14m........144,2 lei
5m..........x => 14× = 5 * 144,2 =>14x=721 => x= 721 : 14 => x = 51,5 lei costă 5 metri de panza
