Posted by **Jen** on Tuesday, June 2, 2009 at 11:25pm.

Please solve for the interval notation corresponding to the set notation

{x | x < –7}

- Algebra -
**MathMate**, Tuesday, June 2, 2009 at 11:29pm
See answer to Rachale's question.

http://www.jiskha.com/display.cgi?id=1243987256

- Algebra -
**Jen**, Tuesday, June 2, 2009 at 11:32pm
Thank you, but why is it

(-infinity -7)?

is it translated to

negative infinity - 7?

- Algebra -
**MathMate**, Tuesday, June 2, 2009 at 11:38pm
> [-5,8) is the same as {x|-5=<x<8}

meaning that the square bracket [ includes the lower limit, while the ] includes the upper limit. The limits are separated by a comma.

You are right in actual practice, it is normal to exclude infinity or negative infinity. In my books, -infinity is a short form for negative infinity.

So the correct answer would be:

**(negative infinity, -7)**

- Algebra -
**Jen**, Wednesday, June 3, 2009 at 12:05am
Thank you for the explanation!

## Answer this Question

## Related Questions

- math - Please help. Hi, I am having some problems with inequalities. It is ...
- Algebra - Write the interval notation corresponding to the set notation {x | x &...
- Algebra - Write the interval notation corresponding to the set notation {x | x &...
- Algebra - Write the interval notation corresponding to the set notation {x | x &...
- Algebra - Solve and express in interval notation Solve: |5 – 8x| > 11 and ...
- math-inequalities - Hi, I am having some problems with inequalities. It is ...
- Math Help Please - Please show me how to put this in interval notation. Thanks! ...
- Solve Inequality - Solve the inequality. Express your solution using interval ...
- Algebra 2 - Use interval notation to represent each set of numbers. 1. -15 < ...
- Algebra 2 - [3y+6]>or equal to 21 If you could put this in set notation, ...