how to make a 3x3 matrix a 9x1 matrix?

Hey i have a matrix x=[ 1 4 7; 2 5 8 ;3 6 9]; how do I make this matrix become x=[ 1;2;3;4;5;6;7;8;9];

Answer 1

[Birdman]

 reshape(x,9,1)

or

 x(:) % this creates a column vector out of a matrix