a) \(4x^2+4x+1=0\)
\(\Rightarrow\left(2x+1\right)^2=0\)
\(\Rightarrow2x+1=0\)
\(\Rightarrow2x=-1\)
\(\Rightarrow x=-0,5\)
b) \(x^2-5x+6=0\)
\(\Rightarrow x^2-2x-3x+6=0\)
\(\Rightarrow x\left(x-2\right)-3\left(x-2\right)=0\)
\(\Rightarrow\left(x-2\right)\left(x-3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-2=0\\x-3=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=2\\x=3\end{matrix}\right.\)
c) \(3x^2-9x+6=0\)
\(\Rightarrow3x^2-3x-6x+6=0\)
\(\Rightarrow3x\left(x-1\right)-6\left(x-1\right)=0\)
\(\Rightarrow\left(3x-6\right)\left(x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}3x-6=0\\x-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=2\\x-1\end{matrix}\right.\)
