a) Áp dụng \(A^2-B^2=\left(A-B\right)\left(A+B\right)\)
\(\Rightarrow\left(2x-1-x-3\right)\left(2x-1+x+3\right)=0\)
\(\Rightarrow\left(x-4\right)\left(3x+2\right)=0\)
=> x = 4 hoặc x = -2/3
b) \(\Rightarrow x^3-2x^2-4x+8=0\)
<=> \(\left(x^3-2x^2\right)-\left(4x-8\right)=0\)
<=>\(x^2\left(x-2\right)-4\left(x-2\right)=0\)
<=> \(\left(x-2\right)^2\left(x+2\right)=0\)
=> x = 2 hoặc x = -2
(2x - 1)2 - (x + 3)2 = 0
=> [(2x - 1) - (x + 3)][(2x - 1) + (x + 3)] = 0
=> (2x - 1 - x - 3)(2x - 1 + x + 3) = 0
=> (x - 4)(3x + 2) = 0
\(\Rightarrow\left[{}\begin{matrix}x-4=0\Rightarrow x=4\\3x+2=0\Rightarrow3x=-2\Rightarrow x=-\dfrac{2}{3}\end{matrix}\right.\)
