remove left sidebar from 2014/2015 themes

Use the full-width page templates or create a child theme and remove
<?php get_sidebar( ‘content’ ); ?>
from the page templates you are using.

https://codex.www.ads-software.com/Child_Themes

Thanks, I have tried that and it leaves me with an empty black left sidebar area and content is not centered.

same problem here….can anyone help?

it leaves me with an empty black left sidebar area and content is not centered.

Then you need to modify the CSS code to change the layout of the page – to widen the content section – which is sometimes a bit complicated in a responsive theme.

But why not just use a theme that has the layout you want?

The answers here not very to the point. The steps described below to searched by the reader:

1) create a child theme of 2015, the tutorial links mentioned above.
2) Try to follow the template hierarchy picture in wordpress codes, to know what files to be edited/created.
3) use firebug and study the layout of article / content area and side bar css. This part may be hard.
4) Change it in the child theme css file. And override the actual styles.

Google each of the above topic..