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1习题平面内过一定点P(x0,y0)且在两坐标轴上的截距的绝对值相等的直线有几条?2直观分析(1)在两坐标轴上的截距的绝对值相等的直线分为三类:图3第一类,和直线x-y=0平行的直线系(图1),截距不为0.第二类,和直线x+y=0平行的直线系(图2),截距不为0.第三类,过原点且和坐标轴不重合的
1 How many straight lines in the plane of a certain point P (x0, y0) and the absolute values of the intercepts on the two axes are equal?2 Intuitive analysis (1) The absolute values of the intercepts on the two axes are equal. The straight lines are divided into three categories: the first type in Fig. 3, and the straight line with the straight line xy=0 (Fig. 1). The intercept is not 0. The second type is a straight line parallel to the straight line x+y=0 (Fig. 2) The intercept is not 0. The third category is over the origin and does not coincide with the axis