题目直线y=kxy=kxy=kx过点(x1(x_{1}(x1,y1)y_{1})y1),(x2(x_{2}(x2,y2)y_{2})y2),若x1−x2=1x_{1}-x_{2}=1x1−x2=1,y1−y2=−2y_{1}-y_{2}=-2y1−y2=−2,则kkk的值为（ ）A.111B.222C.−1-1−1D.−2-2−2知识点：正比例函数的图象章节：函数 / 一次函数
