Open Question: Please help math urgent.?

interval notation is simple:
use round brackets for infinity and point that are not included (strictly greater or smaller)
use square bracket for points that are included (greater than or equal, less than or equal)
combine multiple intervals using union

x = -2 and x < 4
since -2 is included, and 4 is not we get
[-2,4)

x < -2 or x = 3
here -2 is not included but 3 is
(-infinity, -2)U[3,infinity)

-4 < a + 2 < 10
this is two inequalities, each should be solved separately
first we have:
-4or
a+2>-4
a>-4-2
a>-6
then we also have
a+2<10
a<10-2
a<8

so solution is
(-6,8)
because both -6 and 8 are not included.

last one is
x>=3
x>=6
to satisfy both, we use x>=6
which is
[6,infinity)

note that 6 was included (square bracket)

View the original article here