Toán Lớp 7: 1\2-1/8x=1/16x^2. Giúp mình pl
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 7: 1\2-1/8x=1/16x^2. Giúp mình pl
Comments ( 2 )
Dkxd:x \ne 0\\
\dfrac{1}{2} – \dfrac{1}{{8x}} = \dfrac{1}{{16{x^2}}}\\
\Leftrightarrow \dfrac{1}{{16{x^2}}} + \dfrac{1}{{8x}} – \dfrac{1}{2} = 0\\
\Leftrightarrow {\left( {\dfrac{1}{{4x}}} \right)^2} + 2.\dfrac{1}{{4x}}.\dfrac{1}{4} + \dfrac{1}{{16}} – \dfrac{1}{{16}} – \dfrac{1}{2} = 0\\
\Leftrightarrow {\left( {\dfrac{1}{{4x}} + \dfrac{1}{4}} \right)^2} = \dfrac{9}{{16}}\\
\Leftrightarrow \left[ \begin{array}{l}
\dfrac{1}{{4x}} + \dfrac{1}{4} = \dfrac{3}{4}\\
\dfrac{1}{{4x}} + \dfrac{1}{4} = – \dfrac{3}{4}
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
\dfrac{1}{{4x}} = \dfrac{1}{2} \Leftrightarrow x = \dfrac{1}{2}\\
\dfrac{1}{{4x}} = – 1 \Leftrightarrow x = – \dfrac{1}{4}
\end{array} \right.\left( {tm} \right)\\
Vậy\,x = \dfrac{1}{2};x = – \dfrac{1}{4}
\end{array}$