Đáp án:
`a)`\(\left[ \begin{array}{l}x=5\\x=-1\end{array} \right.\)
`b)`\(\left[ \begin{array}{l}x=3\\x=6\end{array} \right.\)
Giải thích các bước giải:
`a) (x-2)^2=9`
`<=> (x-2)^2-9=0`
`<=> (x-2-3)(x-2+3)=0`
`<=> (x-5)(x+1)=0`
`<=>`\(\left[ \begin{array}{l}x-5=0\\x+1=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=5\\x=-1\end{array} \right.\)
`b) (x-3)^2-3x+9=0`
`<=> (x-3)^2-3(x-3)=0`
`<=> (x-3)(x-3-3)=0`
`<=>(x-3)(x-6)=0`
`<=>`\(\left[ \begin{array}{l}x-3=0\\x-6=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=3\\x=6\end{array} \right.\)