Toán Lớp 8: x^2 + 2x phần 2x + 10 + ( x – 5 /5 ) + ( 50 – 5x )/ 2x^2 + 10x
ko có dấu () đâu nhưng tớ đóng lại để chia ra đợc phân số
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 8: x^2 + 2x phần 2x + 10 + ( x – 5 /5 ) + ( 50 – 5x )/ 2x^2 + 10x
ko có dấu () đâu nhưng tớ đóng lại để chia ra đợc phân số
Comments ( 1 )
DK:x \ne \left\{ { – 5;0} \right\}\\
\dfrac{{{x^2} + 2x}}{{2x + 10}} + \dfrac{{x – 5}}{5} + \dfrac{{50 – 5x}}{{2{x^2} + 10x}}\\
= \dfrac{{{x^2} + 2x}}{{2\left( {x + 5} \right)}} + \dfrac{{x – 5}}{5} + \dfrac{{50 – 5x}}{{2x\left( {x + 5} \right)}}\\
= \dfrac{{5{x^3} + 10{x^2} + 2x\left( {x + 5} \right)\left( {x – 5} \right) + 5\left( {50 – 5x} \right)}}{{10x\left( {x + 5} \right)}}\\
= \dfrac{{5{x^3} + 10{x^2} + 2x\left( {{x^2} – 25} \right) + 250 – 25x}}{{10x\left( {x + 5} \right)}}\\
= \dfrac{{5{x^3} + 10{x^2} + 2{x^3} – 50x + 250 – 25x}}{{10x\left( {x + 5} \right)}}\\
= \dfrac{{7{x^3} + 10{x^2} – 75x + 250}}{{10x\left( {x + 5} \right)}}\\
= \dfrac{{7{x^3} + 35{x^2} – 25{x^2} – 125x + 50x + 250}}{{10x\left( {x + 5} \right)}}\\
= \dfrac{{7{x^2}\left( {x + 5} \right) – 25x\left( {x + 5} \right) + 50\left( {x + 5} \right)}}{{10x\left( {x + 5} \right)}}\\
= \dfrac{{\left( {x + 5} \right)\left( {7{x^2} – 25x + 50} \right)}}{{10x\left( {x + 5} \right)}}\\
= \dfrac{{7{x^2} – 25x + 50}}{{10x}}
\end{array}\)