Hello Student,

It takes two points having two parameters such as two different axes coordinates such as x coordinate and y coordinate or x and z coordinates or y and z coordinates. Here you have given two points that have three parameters each. With this we can find the equation of the plane and not a line.

This is because there are infinite number of lines that pass through this plane. Hence unless specified the axis or something, it is impossible to find out the equation of a specific line. Hope it makes it clear.