\mbox - creates a box just wide enough to hold the text in its argument;no linebreaks are allowed in the text;text appears in \rm.
{ \mbox <text argument>}
\mbox command creates a box just wide enough to hold the text in its argument;no linebreaks are allowed in the text;text appears in \rm.
a + b \mbox{ (are you paying attention?) } = c
a + b \text{ (are you paying attention?) } = c