what is 29=w-11

First add 11 to both sides. $${\mathtt{29}}{\mathtt{\,\small\textbf+\,}}{\mathtt{11}} = {\mathtt{w}}{\mathtt{\,-\,}}{\mathtt{11}}{\mathtt{\,\small\textbf+\,}}{\mathtt{11}}$$ By doing this, you are moving the -11 to the other side.

Next, solve. $${\mathtt{40}} = {\mathtt{w}}$$

You now have the solution.