Bài 2 :
1/ x - $\frac{2}{5}$ = $\frac{-1}{3}$ : $\frac{-25}{6}$
x - $\frac{2}{5}$ = $\frac{-1}{3}$ x $\frac{6}{-25}$
x - $\frac{2}{5}$ = $\frac{-6}{-75}$
x - $\frac{2}{5}$ = $\frac{6}{75}$
x = $\frac{6}{75}$ + $\frac{2}{5}$
x = $\frac{6}{75}$ + $\frac{30}{75}$
x = $\frac{36}{75}$ = $\frac{12}{25}$
2/ (4,5 - 2x) . 1$\frac{4}{7}$ = $\frac{-11}{14}$
(4,5 - 2x) . $\frac{11}{7}$ = $\frac{-11}{14}$
(4,5 - 2x) = $\frac{11}{14}$ : $\frac{11}{7}$
(4,5 - 2x) = $\frac{11}{14}$ x $\frac{7}{11}$
4,5 - 2x = $\frac{77}{154}$
$\frac{9}{20}$ - 2x = $\frac{1}{2}$
2x = $\frac{9}{20}$ - $\frac{1}{2}$
2x = $\frac{9}{20}$ - $\frac{10}{20}$
2x = $\frac{-1}{20}$
x = $\frac{-1}{20}$ : 2
x = $\frac{-1}{20}$ x $\frac{1}{2}$
x = $\frac{-1}{40}$
3/ $\frac{-1}{4}$x + 75%x = -4
$\frac{-1}{4}$x + $\frac{3}{4}$x = -4
x($\frac{-1}{4}$ + $\frac{3}{4}$) = -4
x.$\frac{1}{2}$ = $\frac{-4}{1}$
x = $\frac{-4}{1}$ : $\frac{1}{2}$
x = $\frac{-4}{1}$ x 2
x = $\frac{-8}{1}$ = -8
