I was trying to find this out for the Twenty Eleven theme and came across the solution by accident. You don’t need to amend code, at least not in this theme.
– Go to the PAGE in question and select edit
– At top right in edit mode there is a small box called ‘screen options’
– Checkmark the Discussion box
– Scroll down to bottom of the page
– Uncheck both ‘Allow comments’ and ‘Allow trackbacks…’
– Update the PAGE
You will need to do this for each individual page.
