Помогите) 1,2,3,4 677номер

1) $( \frac{2}{7} x)(- \frac{1}{3} )(- \frac{21}{1} )=-5$
$\frac{42}{21} x=-5$
$2x=-5$
$x=-2.5$
2) $x+( \frac{16}{25} - \frac{4}{5} )=-3 \frac{2}{5} : \frac{5}{6}$
$x+ \frac{16-20}{25}=- \frac{17}{5} * \frac{6}{5}$
$x+ \frac{-4}{25}=- \frac{102}{25} |*25$
$25x-4=- 102$
$25x=-98$
$x=-3.92$
3) $- \frac{3}{7} y=- \frac{6}{7} * \frac{25}{10}$
$- \frac{3}{7} y=- \frac{3}{7} * \frac{25}{5}$
$- \frac{3}{7} y=- \frac{75}{35} |*(-1)$
$\frac{3}{7} y= \frac{75}{35}$
$3y= \frac{7*75}{35}$
$3y=15$
$y=5$
4) $x-(1 \frac{5}{7}- \frac{1}{3})=-1 \frac{2}{7}: \frac{5}{10}$
$x-(1 \frac{15}{21}- \frac{7}{21})=- \frac{9}{7}* \frac{10}{5}$
$x-1 \frac{8}{21}=- \frac{90}{35}}$
$x-1 \frac{8}{21}=- \frac{18}{7}}$
$x=1 \frac{8}{21}- \frac{54}{21}}$
$x= \frac{29}{21}- \frac{54}{21}}$
$x= - \frac{25}{21}}$
$x= - 1\frac{4}{21}}$