Question

Answer 1

Ta có: \(\left(7x-1\right)^2=4\left(1-2x\right)^2\)

=>\(\left(7x-1\right)^2=\left(2-4x\right)^2\)

=>\(\left[{}\begin{matrix}7x-1=2-4x\\7x-1=4x-2\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}7x+4x=2+1\\7x-4x=-2+1\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}11x=3\\3x=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{11}\\x=-\dfrac{1}{3}\end{matrix}\right.\)

Answer 2

(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 .

  Vậy ta có hai nghiệm là  và