how to merge two matrices

I have two matrices with a= 20x6 and b=20x3 how can I merge them as 20x9.

thanks.

Answer 1

[Azzi Abdelmalek]

Horizontal concatenation

 c=[a b]

example

for horizontal concatenation

 a=rand(20,6);
 b=rand(20,3);
 c=[a b]

for vertical concatenation

 a=rand(6,20)
 b=rand(3,20)
 c=[a;b]

[Ede gerlderlands]

Thanks.....