Đáp án:
\(\left( d \right):\,\,x - y + 2 = 0\)
Giải thích các bước giải:
\(\eqalign{
& {Q_{\left( {I;{{180}^0}} \right)}}\,\,la\,\,phep\,\,doi\,\,xung\,\,tam\,\,I \cr
& \Rightarrow {Q_{\left( {I;{{180}^0}} \right)}}\, \equiv {D_I} \cr
& {D_I}\left( d \right) = d'. \cr
& Lay\,\,M\left( {x;y} \right) \in d \cr
& {D_I}\left( M \right) = M'\left( {x';y'} \right) \in d' \cr
& Ta\,\,co:\,\,\left\{ \matrix{
x' = 2.0 - x = - x \hfill \cr
y' = 2.3 - y = 6 - y \hfill \cr} \right. \cr
& \Rightarrow M'\left( { - x;6 - y} \right) \in d' \cr
& \Rightarrow - x - \left( {6 - y} \right) + 4 = 0 \cr
& \Leftrightarrow - x - 6 + y + 4 = 0 \cr
& \Leftrightarrow x - y + 2 = 0 \cr
& \Rightarrow \left( d \right):\,\,x - y + 2 = 0 \cr} \)
