I rested on this tutorial.
After issuing the command with "solve" function:
The output is:
Why there is unknown quantity "y" on the right side?
There's no "Maxima" tag, what a pity! However, I was redirected here by a stackoverflow moderator, so I assume it is not offtopic.
Maxima is a computer algebra system based on a 1982 version of Macsyma. It is written in Common Lisp and runs on all POSIX platforms such as Mac OS X, Unix, BSD, and GNU/Linux as well as under Microsoft Windows. It is free software released under the terms of the GNU General Public License.