[tex]k:y=m_1x+b_1;\ l:y=m_2x+b_2\\\\k\ \perp\ l\ if\ m_1m_2=-1\to m_2=-\dfrac{1}{m_1}\\---------------------\\k:y=x+4;\ l:y=m_2x+b_2\\\\m_1=1\to m_2=-\dfrac{1}{1}=-1\\\\k\ \perp\ l\to l:y=-x+b_2\\\\The\ line\ "l"\ passes\ throught\ the\ point\ (-2;\ 6).\\Subtitute\ x=-2\ and\ y=6\ to\ the\ equation\ of\ the\ line\ "l":\\\\6=-(-2)+b_2\\6=2+b_2\ \ \ |subtract\ 2\ from\ both\ sides\\b_2=4\\\\Answer:\boxed{y=-x+4}[/tex]
