Toán Lớp 8: 3x+5/x^2-5x – 25-x/25-x
tính ( ghi rõ cách quy đồng, đổi dấu..)
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Toán Lớp 8: 3x+5/x^2-5x – 25-x/25-x
tính ( ghi rõ cách quy đồng, đổi dấu..)
Comments ( 2 )
\frac{{3x + 5}}{{{x^2} – 5x}} – \frac{{25 – x}}{{25 – 5x}}\\
= \frac{{3x + 5}}{{5\left( {x – 5} \right)}} – \frac{{25 – x}}{{5\left( {x – 5} \right)}}\\
= \frac{{5\left( {3x + 5} \right) – x\left( {25 – x} \right)}}{{5x\left( {x – 5} \right)}}\\
= \frac{{15x + 25 – 25x + {x^2}}}{{5x\left( {x – 5} \right)}}\\
= \frac{{{x^2} – 10x + 25}}{{5x\left( {x – 5} \right)}}\\
= \frac{{{{\left( {x – 5} \right)}^2}}}{{5x\left( {x – 5} \right)}}\\
= \frac{{x – 5}}{{5x}}\\
\end{array}\]