If the coefficient matrix A in a homogeneous system of 22 equations in 16 unknowns is known to have rank 5, how many parameters are there in the general solution
Incidentally, is this homework?
I don't know whether you have seen the following concepts, but here goes:
The number of parameters is the dimension of the nullspace of the matrix.
The dimension of the nullspace of any matrix, plus the rank of the matrix, gives you the number of columns of the matrix.
And you have been given both the rank and the number of columns (since there is one column for each unknown), so you should be set!