设P(a,b),P到x轴,y轴的距离之比为3:4,得:3:4=b:a,
b=3/4a.点P为(a,3/4a)
AP=BP.
(a-1)^2+(3/4a-2)^2=(a+3)^2+(3/4a-4)^2 .
解得a=-4.
P(-4,-3)