I've got some questions regarding intersecting planes in three dimensional space.

1) When trying to find the equation of the line at the intersection of two planes, does equating a variable to zero in both equations work in all situations?

2) I found a small blurb in my textbook about another method for finding the equation of this intersection, but it didn't really go into much detail.  Here is what is said:

"Another way to find the line of intersection is to solve the equation of the planes for two of the variables in terms of the third, which can be taken as the parameter."

Thanks in advance for any assistance.