What do they mean by “bottom line” and why did US IRS turned back 810 millions to IBM? and what do they mean by “unspecified “ layoffs?
As regards your second question,
"Bottom line" is a descriptive term for profits/losses, visualizing that when we calculate whether we had profit or loss,  we start writing revenues then expenses and at the end we have a line that tells us the difference between the two. But since it is the "last line" it is also at the "bottom" of what we have written, hence "bottom line".  

Sometimes it is also used figuratively to indicate the "end result" of something other than financial activity, especially with an intent to brush away reasons and excuses why something did not happen or happened inadequately.