Show that two planes are not the same plane.

linear algebravector-spaces

The plane equations are:

V1 = 2x+3y+z=6

V2 = 4x+6y+2z=9

Now I can see that V2 is not a multiple of V1 due to 9 not being divisible by 2 unlike the other coefficients. But I don't believe it is as simple as that since the question weighs quite a bit. I am also not sure how to represent 2 plane equations being the same.

I tried moving the constant over to the left of each equation and then equating the two to get 2x+3y+z+3=0.

But this is clearly not a sufficient show of how they aren't the same.
Any advice or theory is greatly appreciated.

Best Answer

Dividing the second equation by $2$ we get $$2x+3y+z=\frac{9}{2}\neq 6$$