a) \(4x.\left(2-x\right)+\left(2x+1\right)^2=2\)
\(8x-4x^2+4x^2+4x+1=2\)
\(12x+1=2\)
\(12x=2-1\)
\(12x=1\)
\(x=\frac{1}{12}\)
b) \(\left(x+3\right)^2-5.\left(x+3\right)=0\)
\(\left(x+3\right).\left(x+3-5\right)=0\)
\(\left(x+3\right).\left(x-2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x+3=0\\x-2=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=-3\\x=2\end{cases}}\)