<=>( x-6)(x-2)(x+2)=0
<=>x-6=0 ;x-2=0 hoặc x+2=0
\(\Leftrightarrow\)x=6;x=2 hoặc x=-2
b)
\(\Leftrightarrow\) (2x+5)(2x-3)(2x+3)=0
\(\Leftrightarrow\)2x+5=0;2x-3=0 hoặc 2x+3=0
\(\Leftrightarrow\)x=\(\dfrac{-5}{2}\); x=\(\dfrac{2}{3}\) hoặc x=\(\dfrac{-2}{3}\)
c)x\(^2\)=2x\(\Leftrightarrow\)x\(^2\)-2x=0
\(\Leftrightarrow\)x(x-2)=0
\(\Leftrightarrow\)x=0 hoặc x-2 =0
\(\Leftrightarrow\)x=0 hoặc x=2
e)x\(^2\)-2x+1=4
\(\Leftrightarrow\)(x-1)\(^2\)-4=0
\(\Leftrightarrow\)(x-1)\(^2\)-2\(^2\)=0
\(\Leftrightarrow\)(x-1-2)(x-1+2)=0
\(\Leftrightarrow\)(x-3)(x+1)=0
\(\left\{{}\begin{matrix}x-3=0\\x+1=0\end{matrix}\right.\)
\(\Leftrightarrow\)\(\left\{{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)
