角平分线到角两边距离相等
则设为P(x,y)
则|x+y-3|/√(1²+1²)=|7x-y+4|/√(7²+1²)
5|x+y-3|=|7x-y+4|
所以5x+5y-15=±(7x-y+4)
所以时2x-6y+19=0和12x+4y-11=0