Đáp án:
d) x=1
Giải thích các bước giải:
\(\begin{array}{l}
a){x^2} + 6x + 9 = 2{x^2} - 10x - {x^2} + 3x + 35\\
\to 13x = 26\\
\to x = 2\\
b)9{x^2} - 12x + 4 + 4{x^2} + 12x + 9 + 68 = 18{x^2} - 43x - 5 - 5{x^2}\\
\to 43x = - 86\\
\to x = - 2\\
c)\dfrac{{4\left( {x + 4} \right) - 6\left( {x - \dfrac{{x - 1}}{2}} \right)}}{{12}} = \dfrac{{6\left( {6 - 2x} \right) - 3\left( {x - 3} \right)}}{{12}}\\
\to 4\left( {x + 4} \right) - 6\left( {x - \dfrac{{x - 1}}{2}} \right) = 6\left( {6 - 2x} \right) - 3\left( {x - 3} \right)\\
\to 4x + 16 - 6x + 3x - 3 = 36 - 12x - 3x + 9\\
\to 16x = 32\\
\to x = 2\\
d)\dfrac{{12x + 3\left( {\dfrac{{2x - 5}}{3} - 4x + \dfrac{{2x - 2}}{5}} \right)}}{{12}} = \dfrac{{4\left( {2 - 5x - \dfrac{{6 - 3x}}{4}} \right) - 6\left( {x - 3} \right)}}{{12}}\\
\to 12x + 3\left( {\dfrac{{2x - 5}}{3} - 4x + \dfrac{{2x - 2}}{5}} \right) = 4\left( {2 - 5x - \dfrac{{6 - 3x}}{4}} \right) - 6\left( {x - 3} \right)\\
\to 12x + 2x - 5 - 12x + \dfrac{{6x - 6}}{5} = 8 - 20x - 6 + 3x - 6x + 18\\
\to 25x + \dfrac{{6x - 6}}{5} = 25\\
\to 125x + 6x - 6 = 125\\
\to 131x = 131\\
\to x = 1
\end{array}\)
