State the relationship between the following two planes:
$\begin{aligned}
-x + 3y -z &= 2 \\
x - 4y + z &= 2. \end{aligned}$

What is the volume of the tetrahedron formed by the plane $6x + 3y + 4z - 72 = 0$ and the three coordinate planes?

If the following planes all intersect at the same line, what is the value of $a+ b:$$\begin{aligned}
P_1 &: 3x + ay + 2z -2 =0 \\
P_2 &: 2x + by - 2z + a = 0 \\
P_3 &: 3x - y + 2z + b = 0? \end{aligned}$

State the relationship between the following two planes:
$\begin{aligned}
2x - y + 2z &= -5 \\
x - 3y + 4z &= 3. \end{aligned}$

State the relationship between the planes:
$\begin{aligned}
3x + y - 2z &= -4 \\
- 6x - 2y + 4z &= 1. \end{aligned}$