- I’m assuming the expression implies the following:
(1-n)/(n^2 - 1)
The steps goes as follows:
= -(n-1)/(n^2-1) (factored a negative out)
= -(n-1)/[(n+1)(n-1)] (Factored denominator into a difference of squares, but don’t just blindly accept the fact, expand it and you should get the original denominator)
At this point, the (n-1) terms cancel, as you should know: a real number, besides 0, over itself is 1.
= -1/(n+1) , which is the answer
Note: You could also see it as 1/-(n+1) or 1/(-n-1)
I believe it’s A — atoms in solids are closest together, atoms in liquids are close, but not as compact as in solids, and atoms in gasses aren’t close are all, and they’re constantly moving.
