The line l1 l_1\,l1 has equation 2y+4x+7=02y + 4x + 7 = 02y+4x+7=0
The line l2 l_2\,l2 has equation y=mx+4y = mx + 4y=mx+4, where m m\,m is a constant.
Given that l1 l_1\,l1 and l2 l_2\,l2 are perpendicular.
Find the value of mmm.
Find the coordinates of the point where l1 l_1\,l1 and l2 l_2\,l2 meet.