Question

\(\sqrt{9x^2-6x+1}=2\)

giải phương trình

Answer 1

\(\Leftrightarrow\sqrt{\left(3x-1\right)^2}=2\)

\(\Leftrightarrow\left|3x-1\right|=2\)

\(\Leftrightarrow\left[{}\begin{matrix}3x-1=2\\3x-1=-2\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=1\\x=-\frac{1}{3}\end{matrix}\right.\)

Answer 2

CÁCH KHÁC :

\(\Leftrightarrow9x^2-6x+1=4\)

\(\Leftrightarrow9x^2-6x-3=0\)

\(\Leftrightarrow3\left(x-1\right)\left(3x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\3x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-\frac{1}{3}\end{matrix}\right.\)

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