a: \(\Leftrightarrow\left[{}\begin{matrix}2x=x+3\left(x>=0\right)\\2x=-x-3\left(x< 0\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)
b: \(\Leftrightarrow\left[{}\begin{matrix}-3x=4x-5\left(x< =0\right)\\3x=4x-5\left(x>0\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-7x=-5\\-x=-5\end{matrix}\right.\)
c: \(\Leftrightarrow\left[{}\begin{matrix}\dfrac{1}{2}x=3x-10\left(x>=0\right)\\-\dfrac{1}{2}x=3x-10\left(x< 0\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-\dfrac{5}{2}x=-10\\-\dfrac{7}{2}x=-10\end{matrix}\right.\Leftrightarrow x=4\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{7}\left(loại\right)\\x=5\left(nhận\right)\end{matrix}\right.\)
a, x >= -3
\(\left[{}\begin{matrix}2x=x+3\\2x=-x-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)(tm)
b, đk : x >= 5/4
\(\left[{}\begin{matrix}-3x=4x-5\\-3x=5-4x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}7x=5\\x=5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{7}\\x=5\end{matrix}\right.\)(tm)
c, đk : x>= 10/3
\(\left[{}\begin{matrix}\dfrac{1}{2}x=3x-10\\\dfrac{1}{2}x=10-3x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\dfrac{5}{2}x=10\\\dfrac{7}{2}x=10\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=\dfrac{20}{7}\left(ktm\right)\end{matrix}\right.\)
d, đk : x >= 8/1,5 = 16/3
\(\left[{}\begin{matrix}-\dfrac{5}{2}x=\dfrac{3}{2}x-8\\-\dfrac{5}{2}=8-\dfrac{3}{2}x\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-4x=-8\\-x=8\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-8\end{matrix}\right.\)(ktm)
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