I have been at this same problem for a few hours now. The scan of the paper is above. I'm trying to find the parametric and symmetric equations for the line of intersection for the planes:

3x - 3y - 7z = -4 and x - y + 2z = 3.

I thought I had it solved but if i plug the parametric equations into the original equations neither comes out right. It would if one of the signs where different for the 13t in the parametric equations. But I don't know where I dropped it.

Please help find my mistake or what I'm doing wrong.

Thank you.