Lời giải:
a.
$\frac{4}{5}+\frac{7}{6}:x=\frac{1}{6}$
$\frac{7}{6}:x=\frac{1}{6}-\frac{4}{5}=\frac{-19}{30}$
$x=\frac{7}{6}: \frac{-19}{30}$
$x=\frac{-35}{19}$
b. $\frac{2}{9}-\frac{7}{8}.x=1$
$\frac{7}{8}x=\frac{2}{9}-1=\frac{-7}{9}$
$x=\frac{-7}{9}: \frac{7}{8}$
$x=\frac{-8}{9}$
c. $\frac{5}{9}-\frac{x}{-1}=\frac{-1}{3}$
$\frac{5}{9}+x=\frac{-1}{3}$
$x=\frac{-1}{3}-\frac{5}{9}$
$x=\frac{-8}{9}$
d. $\frac{1}{2}x-5=\frac{-1}{4}$
$\frac{1}{2}x=\frac{-1}{4}+5=\frac{19}{4}$
$x=\frac{19}{4}: \frac{1}{2}$
$x=\frac{19}{2}$
a) 4/5 + 7/6 : x = 1/6
7/6 : x = 1/6 - 4/5
7/6 : x = -19/30
x = 7/6 : -19/30
x = -35/19
b) 2/9 - 7/8 . x = 1
7/8 . x = 1 - 2/9
7/8 . x = 7/9
x = 7/9 : 7/8
x = 8/9
c) 5/9 - x/-1 = -1/3
x/-1 = 5/9 - - 1/3
x/-1 = 8/9
x = -1.8 : 9
x = -8/9
c)1/2x - 5 = -1/4
1/2x = -1/4 + 5
1/2x = 19/4
x = 19/4 : 1/2
x = 19/2