Ta có: \(\left(7x-1\right)^2=4\left(1-2x\right)^2\)
=>\(\left(7x-1\right)^2=\left(2-4x\right)^2\)
=>\(\left[{}\begin{matrix}7x-1=2-4x\\7x-1=4x-2\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}7x+4x=2+1\\7x-4x=-2+1\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}11x=3\\3x=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{11}\\x=-\dfrac{1}{3}\end{matrix}\right.\)
(7x ‒1)2 = 4(1 ‒ 2x)2
(7x ‒ 1)2 ‒ 4(1 ‒ 2x)2 = 0
(7x ‒ 1)2 ‒ [2.(1 ‒ 2x)]2 = 0
(7x ‒ 1)2 ‒ (2 ‒ 4x)2 = 0
[(7x ‒ 1) ‒ (2 ‒ 4x)].[(7x ‒1) + (2 ‒ 4x)] = 0
[7x – 1 – 2 + 4x].[7x – 1 + 2 – 4x] = 0
(11x ‒ 3)(3x + 1) = 0
11x ‒ 3 = 0 hoặc 3x + 1 = 0
11x = 3 hoặc 3x = –1
hoặc 
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Vậy ta có hai nghiệm là và
