not adequately defined in order to solve it. This is because in the first equation you have two different variables, so you can't solve for those variables. In the second and third equations, you can solve for the variables but then that doesn't do anything in the final equation because those variables that you solved for do not appear in that equation.

You can try to make assumptions about what is being calculated in the first three equations and extrapolate that to the final equation, but that's not how math works.