Đáp án:
a) \(P = \dfrac{{x - 1}}{x}\)
Giải thích các bước giải:
\(\begin{array}{l}
B1:\\
a)DK:x \ne \left\{ { - 1;0;1} \right\}\\
P = \left[ {\dfrac{{x + 1}}{{x\left( {x - 1} \right)}}} \right].\dfrac{{{{\left( {x - 1} \right)}^2}}}{{x + 1}}\\
= \dfrac{{x - 1}}{x}\\
b)P = \dfrac{2}{3}\\
\to \dfrac{{x - 1}}{x} = \dfrac{2}{3}\\
\to 3x - 3 = 2x\\
\to x = 3\\
c)\left| {x - 9} \right| = 2x + 6\\
\to \left[ \begin{array}{l}
x - 9 = 2x + 6\left( {DK:x \ge 9} \right)\\
x - 9 = - 2x - 6\left( {DK:x < 9} \right)
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = - 15\left( {KTM} \right)\\
3x = 3
\end{array} \right.\\
\to x = 1\\
Thay:x = 1\\
\to P = \dfrac{{1 - 1}}{1} = 0
\end{array}\)
