what does a sideways 8 and the symbols [ and ( mean on a line chart?

Question

saifoo.khan · Answer

[ means less than and equal to.

( means just less than.

anonymous · Answer

so i have a [ at the seven, and a straight line pointing past the ten

saifoo.khan · Answer

it means, the x is greater than and equal to seven.

saifoo.khan · Answer

can u post the photo here?

anonymous · Answer

with an arrow

saifoo.khan · Answer

yes, thts it.

anonymous · Answer

how wopuld i write that with the sideways 8?

saifoo.khan · Answer

$$x \le 7$$

anonymous · Answer

Sidways eight is
$$\infty$$ 
which means infinity.

saifoo.khan · Answer

but its better if u post a photo!

saifoo.khan · Answer

it depends how u need the answer.

anonymous · Answer

x greater than or equal to seven:
$$x \in [7;\infty[ $$
Or a ) after the infinity symbol. I think the convention is [ for open interval though.

anonymous · Answer

x >=7. Basically, x is anywhere from being equal to 7 to being however large. That's what the interval [7, inf) means.