$\text { a }$) $\text { 2(4x - 3) - 3(x + 5) + 4(x - 10) = 5(x + 2) }$
$\text { ⇔ 8x - 6 - 3x - 15 + 4x - 40 = 5x + 10 }$
$\text { ⇔ (8x - 3x + 4x) - (6 + 15 + 40) = 5x + 10 }$
$\text { ⇔ 9x - 61 = 5x + 10}$
$\text { ⇔ 9x - 5x = 10 + 61 (áp dụng quy tắc chuyển vế) }$
$\text { ⇔ 4x = 71 }$
$\text { ⇔ x = $\frac{71}{4}$ }$
Vậy $\text { x = $\frac{71}{4}$ }$
$\text { b }$) $\text { $\frac{11}{12}$ - ($\frac{2}{5}$ + x) = $\frac{2}{3}$ . (6x + 1) }$
$\text { ⇔ $\frac{11}{12}$ - $\frac{2}{5}$ - x = $\frac{2}{3}$ . 6x +$\frac{2}{3}$ }$
$\text { ⇔ $\frac{55}{60}$ - $\frac{24}{60}$ - x = 4x + $\frac{2}{3}$ }$
$\text { ⇔ $\frac{31}{60}$ - x = 4x + $\frac{2}{3}$ }$
$\text { ⇔ 4x + x = $\frac{31}{60}$ - $\frac{2}{3}$ (áp dụng quy tắc chuyển vế) }$
$\text { ⇔ 5x = $\frac{31}{60}$ - $\frac{40}{60}$ }$
$\text { ⇔ 5x = $\frac{-3}{20}$ }$
$\text { ⇔ x = $\frac{-3}{20}$ : 5 }$
$\text { ⇔ x = $\frac{-3}{20}$ . $\frac{1}{5}$ }$
$\text { ⇔ x = $\frac{-3}{100}$ }$
Vậy $\text { x = $\frac{-3}{100}$ }$
$\text { c }$) $\text { $\frac{7}{3}$ - (2x - $\frac{1}{3}$) = (-2$\frac{1}{6}$ + 1$\frac{1}{2}$) : 0,25 }$
$\text { ⇔ $\frac{7}{3}$ - 2x + $\frac{1}{3}$ = ($\frac{-13}{6}$ + $\frac{3}{2}$) : $\frac{1}{4}$ }$
$\text { ⇔ $\frac{8}{3}$ - 2x = ($\frac{-13}{6}$ + $\frac{9}{6}$) . 4 }$
$\text { ⇔ $\frac{8}{3}$ - 2x = $\frac{-2}{3}$ . 4 }$
$\text { ⇔ $\frac{8}{3}$ - 2x = $\frac{-8}{3}$ }$
$\text { ⇔ 2x = $\frac{8}{3}$ + $\frac{8}{3}$ }$
$\text { ⇔ 2x = $\frac{16}{3}$ }$
$\text { ⇔ x = $\frac{16}{3}$ : 2 }$
$\text { ⇔ x = $\frac{16}{3}$ . $\frac{1}{2}$ }$
$\text { ⇔ x = $\frac{8}{3}$ }$
$\text { Vậy x = $\frac{8}{3}$ }$
$\text { d }$) $\text { 0,75 + $\frac{5}{9}$ : x = 5$\frac{1}{2}$ }$
$\text { ⇔ $\frac{3}{4}$ + $\frac{5}{9}$ : x = $\frac{11}{2}$ }$
$\text { ⇔ $\frac{5}{9}$ : x = $\frac{11}{2}$ - $\frac{3}{4}$ }$
$\text { ⇔ $\frac{5}{9}$ : x = $\frac{22}{4}$ - $\frac{3}{4}$ }$
$\text { ⇔ $\frac{5}{9}$ : x = $\frac{19}{4}$ }$
$\text { ⇔ x = $\frac{5}{9}$ : $\frac{19}{4}$ }$
$\text { ⇔ x = $\frac{5}{9}$ . $\frac{4}{19}$ }$
$\text { ⇔ x = $\frac{20}{171}$ }$
$\text { Vậy x = $\frac{20}{171}$ }$
