2006-I-12
答案:(a) $(4,4)$ (b) $2x+y-12=0$, $(6,0)$ (c) (i) $4x-5y-8=
… Read $\begin{array}{rcl}
x – y & =
$\begin{array}{rcl}
5x – 3y & = &
留意直線 $x+2y+3=0$ 的斜率為 $-\dfrac{1}{2}$
$\begin{array}{cl}
= & \tan 30^\cir
$\begin{array}{rcl}
AP & =
$\begin{array}{cl}
= & \tan(180^\cir
而直線 $kx-3y+