Question

решите пожалуйста 2 1/7:x=2 19/28:3 3/4​

Answer 1

Ответ:

2 1/7:x=2 19/28:3 3/4​;

$2\frac{1}{7} :x=2\frac{19}{28}:3\frac{3}{4};\\\\\frac{2\frac{1}{7}}{x} =\frac{2\frac{19}{28}}{3\frac{3}{4}} ;$

Перекрестно умножаем:

$2\frac{1}{7}*3\frac{3}{4}} =2\frac{19}{28} *x;\\\\\frac{7*2+1}{7}*\frac{4*3+3}{4}} =\frac{28*2+19}{28} *x;\\\\\frac{15}{7}*\frac{15}{4}} =\frac{75}{28} *x;\\\\\frac{225}{28} =\frac{75}{28} *x;\\\\-\frac{75}{28} *x=-\frac{225}{28} ;\\\\\frac{75}{28} *x=\frac{225}{28} ;\\\\x= \frac{225}{28} :\frac{75}{28} =\frac{225}{28} *\frac{28}{75} =\frac{225}{1} *\frac{1}{75} =\frac{225}{75} =3.\\\\x=3.$