Question

3) 5/7x + 2 1/7 = 3 3/28 - 4/7x​

Answer 1

5/7x + 2 1/7 = 3 3/28 - 4/7x

4/7x + 5/7 =3 3/28 -2 1/7

9/7x =27/28

x= 27/28 : 9/7

x= 3/4

Ответ: x= 3/4

Answer 2

Ответ:

$x=1\frac{1}{3}$

Пошаговое объяснение:

$\frac{5}{7x} +2\frac{1}{7} =3\frac{3}{28} -\frac{4}{7x} \\\\\frac{5}{7x} +\frac{15}{7} =\frac{87}{28} -\frac{4}{7x} \\\\\frac{20}{28x} +\frac{60x}{28x} =\frac{87x}{28x} -\frac{16}{28x} \\\\\frac{20}{28x} +\frac{60x}{28x} -\frac{87x}{28x} +\frac{16}{28x} =0\\ 20+60x-87x+16=0\\-27x+36=0\\-27x=-36$

$x=\frac{-36}{-27} =\frac{4}{3}$

Проверка:

$\frac{5}{7*\frac{4}{3} } =\frac{5}{\frac{28}{3} } =\frac{15}{28} \\\frac{15}{28} +\frac{15}{7} =\frac{15}{28} +\frac{60}{28} =\frac{75}{28} =2\frac{19}{28} \\\frac{4}{7*\frac{4}{3} } =\frac{4}{\frac{28}{3} } =\frac{12}{28} \\\\\frac{87}{28} -\frac{12}{28} =\frac{75}{28} =2\frac{19}{28}$

$2\frac{19}{28} =2\frac{19}{28}$