Đáp án:
B2:
b) \(x = \dfrac{{17}}{9}\)
Giải thích các bước giải:
\(\begin{array}{l}
B1:\\
DK:\left\{ \begin{array}{l}
x - 1 \ne 0\\
2 - x \ne 0
\end{array} \right. \to x \ne \left\{ {1;2} \right\}\\
B2:\\
a)\dfrac{{5\left( {x - 2} \right) - 20.5 + 4\left( {3 - 2x} \right)}}{{20}} = 0\\
\to 5x - 10 - 100 + 12 - 8x = 0\\
\to - 3x - 98 = 0\\
\to x = - \dfrac{{98}}{3}\\
b)DK:x \ne \left\{ {3;5} \right\}\\
\dfrac{{x - 5 + {x^2} - 9 + 12 - \left( {x - 3} \right)\left( {x - 5} \right)}}{{\left( {x - 3} \right)\left( {x - 5} \right)}} = 0\\
\to \dfrac{{{x^2} + x - 2 - {x^2} + 8x - 15}}{{\left( {x - 3} \right)\left( {x - 5} \right)}} = 0\\
\to 9x - 17 = 0\\
\to x = \dfrac{{17}}{9}
\end{array}\)
