Đáp án:
$\begin{array}{l}
a)\dfrac{{x + 1}}{9} - \dfrac{{x - 1}}{6} = 2 - \dfrac{{x + 3}}{2}\\
\Rightarrow \dfrac{{2.\left( {x + 1} \right) - 3.\left( {x - 1} \right)}}{{18}} = \dfrac{{2.18 - 9.\left( {x + 3} \right)}}{{18}}\\
\Rightarrow \dfrac{{2x + 2 - 3x + 3}}{{18}} = \dfrac{{36 - 9x - 27}}{{18}}\\
\Rightarrow - x + 5 = 9 - 9x\\
\Rightarrow - x + 9x = 9 - 5\\
\Rightarrow 8x = 4\\
\Rightarrow x = \dfrac{1}{2}\\
Vậy\,x = \dfrac{1}{2}\\
b)\dfrac{{3x + 5}}{5} - \dfrac{{x + 1}}{3} = 1\\
\Rightarrow \dfrac{{3\left( {3x + 5} \right) - 5\left( {x + 1} \right)}}{{15}} = 1\\
\Rightarrow 9x + 15 - 5x - 5 = 15\\
\Rightarrow 4x + 10 = 15\\
\Rightarrow 4x = 5\\
\Rightarrow x = \dfrac{5}{4}\\
Vậy\,x = \dfrac{5}{4}\\
c)5 - \dfrac{{1 - 2x}}{4} = \dfrac{{3x + 20}}{6} + \dfrac{x}{3}\\
\Rightarrow \dfrac{{5.12 - 3.\left( {1 - 2x} \right)}}{{12}} = \dfrac{{2.\left( {3x + 20} \right) + 4x}}{{12}}\\
\Rightarrow 60 - 3 + 6x = 6x + 40 + 4x\\
\Rightarrow 4x = 60 - 3 - 40\\
\Rightarrow 4x = 17\\
\Rightarrow x = \dfrac{{17}}{4}\\
Vậy\,x = \dfrac{{17}}{4}\\
d)\dfrac{{6y + 7}}{4} + \dfrac{{8 - 5y}}{3} = 5\\
\Rightarrow \dfrac{{3\left( {6y + 7} \right) + 4\left( {8 - 5y} \right)}}{{12}} = 5\\
\Rightarrow 18y + 21 + 32 - 20y = 60\\
\Rightarrow 2y = - 7\\
\Rightarrow y = - \dfrac{7}{2}\\
Vậy\,y = - \dfrac{7}{2}\\
e)\dfrac{{2z - 1}}{6} - \dfrac{{z + 1}}{3} = z\\
\Rightarrow \dfrac{{2z - 1 - 2z - 2}}{6} = z\\
\Rightarrow - 3 = 6z\\
\Rightarrow z = - \dfrac{1}{2}\\
Vậy\,z = - \dfrac{1}{2}
\end{array}$
