Bài 26:
a) x - $\frac{1}{8}$ - $\frac{2}{9}$ = $\frac{47}{72}$
x - $\frac{1}{8}$ = $\frac{47}{72}$ + $\frac{2}{9}$
x - $\frac{1}{8}$ = $\frac{7}{8}$
x = $\frac{7}{8}$ + $\frac{1}{8}$
x = 1
b) $\frac{15}{36}$ - x : $\frac{2}{5}$ = $\frac{1}{4}$
x : $\frac{2}{5}$ = $\frac{15}{36}$ - $\frac{1}{4}$
x : $\frac{2}{5}$ = $\frac{1}{6}$
x = $\frac{1}{6}$ x $\frac{2}{5}$
x = $\frac{1}{15}$
c) 1 - ($\frac{4}{9}$ + x - $\frac{7}{8}$) : $\frac{3}{4}$ = 0
$\frac{5}{9}$ + x - $\frac{7}{6}$ = 0
$\frac{5}{9}$ + x = 0 + $\frac{7}{6}$
$\frac{5}{9}$ + x = $\frac{7}{6}$
x = $\frac{7}{6}$ - $\frac{5}{9}$
x = $\frac{11}{18}$
f) ($\frac{2}{24}$ + $\frac{2}{48}$ + $\frac{2}{80}$ + $\frac{2}{120}$) x x + $\frac{3}{5}$ = $\frac{14}{15}$
$\frac{1}{6}$ x x + $\frac{3}{5}$ = $\frac{14}{15}$
$\frac{1}{6}$ x x = $\frac{14}{15}$ - $\frac{3}{5}$
$\frac{1}{6}$ x x = $\frac{1}{3}$
x = $\frac{1}{3}$ : $\frac{1}{6}$
x = 2
