Find the equation of the plane passing through the line of intersection of the planes x - 2y + z = 1 and 2x + y + z = 8 and parallel to the line with direction ratios 1, 2, 1 ?
1
9x - 8y + 7z - 21 = 0
2
9x + 8y + 7z - 21 = 0
3
9x - 8y + 7z + 21 = 0
4
9x + 8y + 7z + 21 = 0