The line in which the planes
x + y + z = 9, and
2 x - y - z = 3
intersect, is
3 x = 12 (or x = 4)... Is that true of false?
so what I figure out that the line for these two planes to intersect is line[t]={4,5,0}+ t{0,3,-3} = {4,5+3t,-3t}
So from these on can I separate them out and say that the line in which the planes intersect is x = 4?