inequality and interval notation

[Failenn]

trying to do an inequality and also rewriting it as interval notation has me confused especially when its given in a word problem.

example: x is negative. I think that is written x < 0
and in interval notation it is (-infinity, 0)

or Y is at least 5. y > 5, (5, infinity)

but when combined I'm lost...

x is at least 3 but no more than 7. to me this means
3< X < 7 and in interval notation its (3, 7)

is there a list somewhere of words or phrases that could help me figure out which inequality sign I'm supposed to use?

Thanks for any help.

 

[Deleted member 4993]

trying to do an inequality and also rewriting it as interval notation has me confused especially when its given in a word problem.

example: x is negative. I think that is written x < 0
and in interval notation it is (-infinity, 0)

or Y is at least 5. y ? 5, [5, infinity) ? corrected, In this case y = 5 is a valid answer.
but when combined I'm lost...

x is at least 3 but no more than 7. to me this means
3? X ? 7 and in interval notation its [3, 7] ? corrected, In this case x = 3 and x = 7 are valid answers.


is there a list somewhere of words or phrases that could help me figure out which inequality sign I'm supposed to use?

Thanks for any help.

For a good discussion go to:

http://www.sosmath.com/algebra/inequali ... neq02.html