No. You have ONE equation. It just happens that you defined it in 4 pieces, then you added them all up.
If you defined them as constants earlier, then you do NOT want to define those other variables in the syms call. If you did that, it would overwrite the values for those constants. Similarly, putting this line in your code,
again overwrites the variables you just created. That just undid all the work you did in the previous lines. So DELETE that use of syms. If you don't believe me, consider this example:
So at this point, X is defined. It has the value 3. MATLAB tells us that.
Here X no longer has the value 3. It is just a simple symbolic parametre, with comepletely unknown value.
Anyway, when you use that call to solve, what does it show? (Nothing is sent.) MATLAB does not use mail in any form. Why do you think nothing happens?
If all of the other parameters are known, then you have what is merely a 4th degree polynomial in the unknown, so it should be solvable.