Tìm x biết \(\left| {\frac{1}{3} - 3x} \right| = 1\frac{1}{5}\)
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Lời giải:
Báo sai\(\begin{array}{l} \left| {\frac{1}{3} - 3x} \right| = 1\frac{1}{5}\\ \Rightarrow \left| {\frac{1}{3} - 3x} \right| = \frac{6}{5}\\ \Rightarrow \frac{1}{3} - 3x = \frac{6}{5}\,\,\,hay\,\,\,\frac{1}{3} - 3x = - \frac{6}{5}\\ \Rightarrow - 3x = \frac{6}{5} - \frac{1}{3}\,\,\,hay\,\, - 3x = - \frac{6}{5} - \frac{1}{3}\\ \Rightarrow - 3x = \frac{{13}}{{15}}\,\,\,\,\,hay\,\,\,\, - 3x = \frac{{ - 23}}{{15}}\\ \Rightarrow x = \frac{{13}}{{15}}:\left( { - 3} \right)\,\,\,\,\,hay\,\,\,\,x = \frac{{ - 23}}{{15}}:\left( { - 3} \right)\\ \Rightarrow x = \frac{{13}}{{15}}.\frac{1}{{ - 3}}\,\,\,\,\,hay\,\,\,\,x = \frac{{ - 23}}{{15}}.\frac{1}{{ - 3}}\\ \Rightarrow x = \frac{{ - 13}}{{45}}\,\,\,\,\,hay\,\,\,\,x = \frac{{23}}{{45}} \end{array}\)
