# Math Help - Meaning of x:x < 9

1. ## Meaning of x:x < 9

Actually it's C={x:x < 9}, does that mean x is lesser than 9 ?

Thanks

2. ## Re: Meaning of x:x < 9

Originally Posted by FailInMaths
Actually it's C={x:x < 9}, does that mean x is lesser than 9 ?

Thanks
Yes, you're right. $C=\{x:x<9\}$ is the set theoretic way of saying the interval $(-\infty,9)$.

3. ## Re: Meaning of x:x < 9

Originally Posted by Chris L T521
Yes, you're right. $C=\{x:x<9\}$ is the set theoretic way of saying the interval $(-\infty,9)$.
Thanks !