When doing linear inequalities, how do you know when to use a closed/open dot?

Question

I'm not sure when to use closed/open.

Thanks

Answer 1

Use a closed dot at a place where you have "less than or equal to" or "greater than or equal to."

Use an open dot at a place where you have "less than" or "greater than."

For example, when graphing the inequality x > 2, the number 2 is NOT a solution (because 2 is NOT bigger than 2), so you want an open dot at 2.

On the other hand, when graphing the inequality 1 ≤ x < 3, 1 IS a solution (it is true that 1 ≤ 1 < 3), so you want a closed dot at 1. However, 3 is NOT a solution (because it isn't true that 1 ≤ 3 < 3), so you want an open dot at 3.

Answer 2

when the sign has a line under it it's closed dot which means it's included

for instance < is open.. but it it had a line under it it would have been closed