How to run solver automatically when any cell in sheet is changed?

I use solver to calculate a value in a sheet from variables that are entered in cells. I would like to automatically run solver as soon as any value in any cell is changed. How can I achieve this?

With formulas and functions you can’t get the result?

No, I need to solve a linear equation, and want to trigger solver from a macro. Actually, it might be better to use a button than to run it every time a cell is changed, since it takes a few secs to run …