for some , , and from the question and part (b).
It is easy to see that the line is just the intersection of plane , i. e., any point on the line has to satisfy both equations. Thus we have following equation for line .
Now let's find out the relation among parameters .
The first coordinate shows , while the third shows . Summing these equations gives , hence . Substituting it back gives: for any point on line it satisfies
which has is equivalent equation form; for any point on the line satisfies