how do I make single character as a variable in an array

[Guest]

I am trying to enter one character, a, in a matrix array, then use mmult() to
multiply that matrix with one with no variables so I can see the solution in
terms of the variable. They are both 3x3 matrices but I get errors for the
3x3 matrix solution. I assume it is not accepting ,a, as an input. I have
tried ={"a"} also an every variation in between. Will Excel accept a
character as a variable in an array?
Thanks for any assistance.

 

[R.VENKATARAMAN]

have I understood the problem???

you want to enter in all the cells of a 3x3 matrix or a range of 3rows and 3
columns
highlight this range and type a and hit control+shift+enter