In?the?rectangular?coordinates,abscissa?and?ordinate?of?the?intersection?point?oft

发布时间:2020-07-30 06:47:41

In?the?rectangular?coordinates,abscissa?and?ordinate?of?the?intersection?point?of the?lines?y=x-k and?y=kx+2 are?integers?for?imteger?k,then?the?number?of?the?possible?values?of?k is
(英汉小词典:abscissa横坐标;ordinate纵坐标;intersectionpoint交点;integer整数)A.4B.5C.6D.7

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A
解析分析:让直线y=x-k,y=kx+2组成方程组,消去y,根据x,k均为整数求得k可能的整数解的个数即可.

解答:,x-k=kx+2,(x+1)k=x-2,k=1+,∵x+1可取±1,±3共4个数,∴相对应的k的值也要有4个.故选A.

点评:本题考查了直线的相交问题;组成方程组消去一个未知数是解决本题的突破点;找相应的整数解是解决本题的难点.
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