Rút gọn biểu thức: (6x + 1)^2 + (6x – 1)^2 – 2(1 + 6x)(6x – 1)

* Hướng dẫn giải

$$\begin{gathered} {\left(6x+1\right)}^2+{\left(6x-1\right)}^2-2\left(1+6x\right)\left(6x-1\right) \\ ={\left(6x+1\right)}^2-2\left(1+6x\right)\left(6x-1\right)+{\left(6x-1\right)}^2 \\ ={\left[\left(6x+1\right)-\left(6x-1\right)\right]}^2 \\ ={\left(6x+1-6x+1\right)}^2=2^2=4 \end{gathered}$$