I read a the following link with state that the Qualitative Research does't have Variables.
https://faculty.unlv.edu/pjones/rmqual.htm
If you don't agree with this academic site so, what is the variables in the following research problem:
1- What is the formulation for the research problem which find out the binary search algorithm.
2- What is the formulation for the research problem which solve shortest path problem algorithm.
3- What is the solution of mathematical equation.
generally find a way to solve a know problem may not required variables.