Explicație pas cu pas:
1)
[tex] \frac{x}{65} = \frac{4}{10} \\ x = \frac{65 \times 4}{100} = > x = \frac{13}{5} = 2.6[/tex]
2)
[tex] \frac{0.4}{x} = \frac{1.75}{0.7} \\ x = \frac{0.4 \times 0.7}{1.75} = > x = \frac{4}{25} = 0.16 [/tex]
3)
[tex] \frac{2x}{17} = \frac{4}{5} \\ x = \frac{17 \times 4}{2 \times 5} = > x = \frac{34}{5} = 6.8[/tex]
4)
[tex] \frac{2}{x + 1} = \frac{3}{x + 2} \\ [/tex]
[tex]3(x + 1) = 2(x + 2) \\ 3x + 3 = 2x + 4 \\ 3x - 2x = 4 - 3 \\ x = 1[/tex]
