Toán Lớp 10: 4/x+1+1=2x+1/2x-1
2x/x+2-3x+2/3-x+7=0
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 10: 4/x+1+1=2x+1/2x-1
2x/x+2-3x+2/3-x+7=0
Comments ( 1 )
a)Dkxd:x \ne – 1;x \ne \dfrac{1}{2}\\
\dfrac{4}{{x + 1}} + 1 = \dfrac{{2x + 1}}{{2x – 1}}\\
\Leftrightarrow \dfrac{{4 + x + 1}}{{x + 1}} = \dfrac{{2x + 1}}{{2x – 1}}\\
\Leftrightarrow \left( {x + 5} \right).\left( {2x – 1} \right) = \left( {x + 1} \right)\left( {2x + 1} \right)\\
\Leftrightarrow 2{x^2} – x + 10x – 5 = 2{x^2} + x + 2x + 1\\
\Leftrightarrow 9x – 5 = 3x + 1\\
\Leftrightarrow 6x = 6\\
\Leftrightarrow x = 1\left( {tm} \right)\\
Vậy\,x = 1\\
b)Dkxd:x \ne – 2;x \ne 3\\
\dfrac{{2x}}{{x + 2}} – \dfrac{{3x + 2}}{{3 – x}} + 7 = 0\\
\Leftrightarrow \dfrac{{2x\left( {3 – x} \right) – \left( {3x + 2} \right)\left( {x + 2} \right) + 7\left( {x + 2} \right)\left( {3 – x} \right)}}{{\left( {x + 2} \right)\left( {3 – x} \right)}} = 0\\
\Leftrightarrow 6x – 2{x^2} – \left( {3{x^2} + 8x + 4} \right) + 7\left( {3x – {x^2} + 6 – 2x} \right) = 0\\
\Leftrightarrow 6x – 2{x^2} – 3{x^2} – 8x – 4 – 7{x^2} + 7x + 42 = 0\\
\Leftrightarrow – 12{x^2} + 5x + 38 = 0\\
\Leftrightarrow \left( { – 12x – 19} \right)\left( {x – 2} \right) = 0\\
\Leftrightarrow x = – \dfrac{{19}}{{12}};x = 2\left( {tmdk} \right)\\
Vậy\,x = – \dfrac{{19}}{{12}};x = 2
\end{array}$