overbar

HTML, CSS: overbar matching square root symbol

Is there a way in HTML4 and/or CSS to do the following, but then correctly: (2) How can I move my expression to the left, under the ¯ symbols, such that they overlap eachother? Note: it should work on every font-size. Thanks! (My current code, thank you Matthew Jones(+1) for the text-decoration: overline, lacks the scalin...