Giải thích các bước giải:
1. a) `4/11 x - 1/3= 2/5`
`⇒ 4/11 x = 2/5 + 1/3`
`=> 4/11 x = 11/15`
`=> x = 11/15 : 4/11`
`=> x = 11/15 . 11/4`
`=> x = 121/60`
b) `(-6)/7 - 1/5 x = -4`
`=> 1/5 x = (-6)/7 - (-4)`
`=> 1/5 x = 22/7`
`=> x = 22/7 : 1/5`
`=> x = 22/7 . 5`
`=> x = 110/7`
c) `1/4 + (-4)/3 x = (-7)/5`
`=> (-4)/3 x= (-7)/5 - 1/4`
`=> (-4)/3 x = (-33)/20`
`=> x = (-33)/20 : (-4)/3`
`=> x =(-33)/20 . (-3)/4`
`=> x = 99/80`
d) `(-5)/2 + x : 7 = (-1)/3`
`=> x : 7 = (-1)/3 - (-5)/2`
`=> x : 7 = 13/6`
`⇒ x = 13/6 . 7`
`=> x= 91/6`
2. a) `|x + 3/4| - 1/5 = 0`
`=> |x + 3/4| = 1/5`
\(⇒\left[ \begin{array}{l}x+\dfrac{3}{4}=\dfrac{1}{5}\\x+\dfrac{3}{4}=\dfrac{-1}{5}\end{array} \right.\)
\(⇒\left[ \begin{array}{l}x=\dfrac{1}{5}-\dfrac{3}{4}\\x=\dfrac{-1}{5}-\dfrac{3}{4}\end{array} \right.\)
\(⇒\left[ \begin{array}{l}x=\dfrac{-11}{20}\\x=\dfrac{-19}{20}\end{array} \right.\)
Vậy `x ∈ {(-11)/20; (-19)/20}`
b) `|2x- 5/6|=0`
`=> 2x - 5/6 = 0`
`=> 2x = 5/6`
`=> x = 5/12`
c) `|7/3 - x| - 5/8 = 3/4`
`=> |7/3 - x| = 3/4 + 5/8`
`=> |7/3 - x| = 11/8`
\(⇒\left[ \begin{array}{l}\dfrac{7}{3}-x=\dfrac{11}{8}\\\dfrac{7}{3}-x=\dfrac{-11}{8}\end{array} \right.\)
\(⇒\left[ \begin{array}{l}x=\dfrac{7}{3}-\dfrac{11}{8}\\x=\dfrac{7}{3}-\dfrac{-11}{8}\end{array} \right.\)
\(⇒\left[ \begin{array}{l}x=\dfrac{23}{24}\\x=\dfrac{89}{24}\end{array} \right.\)
Vậy `x ∈ {23/24; 89/24}`
3. a) `5/7 x - 4/3 = 5/9 - 1/7 x`
`⇔ 5/7 x + 1/7 x = 5/9 + 4/3`
`⇔ 6/7 x = 17/9`
`<=> x = 17/9 : 6/7`
`<=> x = 17/9 . 7/6`
`<=> x = 119/54`
b) `2/9 - (5/4 x - 1/3) = 5/9 - 1/2 x`
`⇒ 2/9 - 5/4 x +1/3 = 5/9 - 1/2 x`
`=> (-5)/4 x + 1/2 x = 5/9 - 2/9 - 1/3`
`=> (-3)/4 x = 0`
`=> x = 0`
