MATLAB can't find the solution of the equation with solve.

You should describe the problem more clearly, what equation, what to seek. If it is a nonlinear equation, you should use the fsolve command, first write the equation into the function file and call fsolve to solve the function file. This command is not necessarily the exact solution, and it is not necessarily the solution you want, so you can set the initial value several times to see what the final calculation result is.