As far as I have seen, when it comes to solving linear systems of equations it is assumed to have a matrix with a number of rows and columns equal to a power of two, but what if it is not the case?
If for instance I have the equation $Ax=b$ where A is a 4x4 matrix and x and b 4x1 vectors, I expect to find the solution in terms of amplitudes of the 4 basis states considered for the problem. What if instead of 4 there is 5? My idea would be to choose an Hilbert space of smallest dimension that it includes 5 i.e. 8, and then make it so that 3 basis states will have amplitude 0. Is it correct to reason in this way, or am i making problems for nothing?