Các bước giải:
2
a/
-$\frac{5}{9}$ + x = $\frac{4}{9}$
x = $\frac{4}{9}$ - $\frac{-5}{9}$
x = 1
b/
$\frac{3}{4}$ + $\frac{1}{4}$ x = $\frac{-5}{6}$
$\frac{1}{4}$ x = $\frac{-5}{6}$ - $\frac{3}{4}$
$\frac{1}{4}$ x = -$\frac{19}{12}$
⇒ x = -$\frac{13}{9}$
c/|x - $\frac{2}{5}$| = 1
⇒ x - $\frac{2}{5}$ = ±1
Nếu x - $\frac{2}{5}$ = 1
⇒ x = 1 + $\frac{2}{5}$ = $\frac{7}{5}$
Nếu x - $\frac{2}{5}$ = -1
⇒ x = -1 + $\frac{2}{5}$ = -$\frac{3}{5}$
⇒ x = 1; -$\frac{3}{5}$
