[填空题]
The diagram shows the straigz f7 ix*b(f-nvyv8 q9dht lineit2 v wk.0zn(h $L_1$, which intersects the $x$-axis at A(−8,0) and the $y$-axis at B(0,4).
1.Write down the coordinates of M, the midpoint of line segment [AB]. (a,b) a= b=
2.Calculate the gradient of $L_1$.
The line $L_2$ is perpendicular to $L_1$ and passes through the point P(1,2). $L_1$ =
3.Find the equation of $L_2$. Give your answer in the form y=mx+c. m = c =
