\(\left(3x-7\right)^{2015}=\left(3x-7\right)^{2017}\)
\(\Leftrightarrow\left(3x-7\right)^{2017}-\left(3x-7\right)^{2015}=0\)
\(\Leftrightarrow\left(3x-7\right)^2=0\)
\(\Leftrightarrow3x-7=0\)
\(\Leftrightarrow3x=7\Leftrightarrow x=\frac{7}{3}\)
Vậy \(x=\frac{7}{3}\)
\(\left(3x-7\right)^{2015}=\left(3x-7\right)^{2017}\)
\(\Rightarrow\left(3x-7\right)^{2017}-\left(3x-7\right)^{2015}=0\)
\(\Rightarrow\left(3x-7\right)^{2015}\left[\left(3x-7\right)^2-1\right]=0\)
\(\Rightarrow\left(3x-7\right)^{2015}=0\) hoặc \(\left(3x-7\right)^2-1=0\)
+) \(\left(3x-7\right)^{2015}=0\Rightarrow3x-7=0\Rightarrow x=\frac{7}{3}\)
+) \(\left(3x-7\right)^2-1=0\Rightarrow\left(3x-7\right)^2=1\)
\(\Rightarrow\left[\begin{matrix}3x-7=1\\3x-7=-1\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=\frac{8}{3}\\x=2\end{matrix}\right.\)
Vậy \(x\in\left\{\frac{7}{3};\frac{8}{3};2\right\}\)
thiếu 1 trường hợp nữa
(3x-7)2015=(3x-1)2017 =1
