[填空题]
The coordinates of pointw,a1x nyq8) qg6gqo :., ohcbly-n)x6 pp8f 9otbmil6i rz+2xzfnx:msr3l 77 A are (−1,−7) and the coordinates of point B are (5,2).r p3)mf ri:iz l xfxt 7nly+7xpm686s2obz -9n $L_1$ is the line which passes through A and B.
1.Find the equation of $L_1$.
Point M is the midpoint of [AB]. The line $L_2$ is perpendicular to $L_1$ and passes through M. y = ax+b a= b =
2.Find the equation of $L_2$. y = ax+b a= b =
