Just because we can’t find a solution, it doesn’t mean there isn’t one.
— Andrew Wiles, English mathematician
Today, you are going to learn how to write equations of straight line in 3D geometry.
Think, if two planes intersect then what geometry we get?
Yes it is straight line.
Simply you can visualize it by taking example of coordinate planes.
Intersection of x-y and y-z planes gives y axis,
Intersection of y-z and z-x planes gives z axis,
Intersection of z-x and x-y planes gives x axis.
For details, go through the following notes;