a: \(x\left(x-2\right)-\left(x+2\right)^2=4x+6\)
=>\(x^2-2x-x^2-4x-4=4x+6\)
=>-6x-4=4x+6
=>-10x=10
=>x=-1
b: x(x-2025)=2023(2025-x)
=>x(x-2025)=-2023(x-2025)
=>(x-2025)(x+2023)=0
=>\(\left[{}\begin{matrix}x-2025=0\\x+2023=0\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=2025\\x=-2023\end{matrix}\right.\)