Question

直线方程两点式化一般式、截距式的化法?

Answer 1

(y-y2)/(y1-y2)=(x-x2)/(x1-x2)

(x1-x2)y-y2(x1-x2)=(y1-y2)x-x2(y1-y2)

(y1-y2)x-(x1-x2)y+(x1y2-x2y2-x2y1+x2y2)=0

截距式

(y1-y2)x-(x1-x2)y=(x2y2+x2y1-x1y2-x2y2)

x/[(x2y2+x2y1-x1y2-x2y2)/y1-y2)]+y/[(x1y2-x2y2-x2y1+x2y2)/(x1-x2)]=1