a) \(\Leftrightarrow8x-4x^2+4x^2+4x+1=2\)
\(\Leftrightarrow12x=1\)
\(\Leftrightarrow x=\frac{1}{12}\)
b) \(\Leftrightarrow\left(x+3\right)\left(x+3-5\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=2\end{matrix}\right.\)
c) \(\Leftrightarrow x\left(11x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\frac{5}{11}\end{matrix}\right.\)
d) \(\Leftrightarrow x^3-6x^2+12x-8=0\)
\(\Leftrightarrow\left(x-2\right)^3=0\)
\(\Leftrightarrow x-2=0\)
\(\Leftrightarrow x=2\)