How run Solver in MatLab

Hi, I am developing a modelization of a absorption column in excel and MatLab. In the beggining of the process i have to give a values arbitrarily to a variable and in the middle of the resolution i have a equation to verify this value. In excel i make a solver to minimize the difference of the 2 equations changing the arbitrated value but i don´t know how to do it in MatLab. Can anyone help me?

Thanks

[Sara]

Do you have to make the difference minimum or zero? Which function do you use in excel?