Ответ:

[tex]x \div 4.2 = 3 \div 5.6[/tex]

[tex] \frac{x}{4.2} = \frac{3}{5.6} [/tex]

[tex]5.6x = 3 \times 4.2[/tex]

[tex] \frac{56}{10} x = 12.6[/tex]

сокращаем на общий делитель 2:

[tex] \frac{28}{5} x = 12.6[/tex]

[tex] \frac{5}{28} \times \frac{28}{5} x = \frac{5}{28} \times 12.6[/tex]

сокращаем на нод 5 и нод 28:

[tex]x = \frac{5}{28} \times 12.6[/tex]

[tex]x = \frac{5}{28} \times \frac{63}{5} [/tex]

сокращаем на нод 5 и нод 7:

[tex]x = \frac{1}{4} \times 9[/tex]

[tex]x = \frac{1}{4} \times \frac{9}{1} [/tex]

[tex]x = \frac{1 \times 9}{4 \times 1} [/tex]

[tex]x = \frac{9}{4} [/tex]

[tex] \frac{x}{4.2} = \frac{3}{5.6} \\ 5.6x = 3 \times 4.2 \\ 5.6x = 12.6 \\ x = \frac{12.6}{5.6} \\ x = 2.25[/tex]