Toán Lớp 8: thực hiện phép tính:
1-x^2/x^2+2x : 2-2x/3x
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Toán Lớp 8: thực hiện phép tính:
1-x^2/x^2+2x : 2-2x/3x
Comments ( 1 )
{x^2} + 2x \ne 0\\
3x \ne 0\\
2 – 2x \ne 0
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x\left( {x + 2} \right) \ne 0\\
x \ne 0\\
x \ne 1
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x \ne – 2\\
x \ne 0\\
x \ne 1
\end{array} \right.$
\dfrac{{1 – {x^2}}}{{{x^2} + 2x}}:\dfrac{{2 – 2x}}{{3x}}\\
= \dfrac{{\left( {1 – x} \right)\left( {1 + x} \right)}}{{x\left( {x + 2} \right)}}.\dfrac{{3x}}{{2.\left( {1 – x} \right)}}\\
= \dfrac{{\left( {1 + x} \right).3}}{{2.\left( {x + 2} \right)}}\\
= \dfrac{{3x + 3}}{{2x + 4}}
\end{array}$