Respuesta :
Explanation
a way of writing subsets of the real number lines is by using intervals,
let's chec
A) closed interval
this includes the endpoints
[tex]\lbrack a,b\rbrack[/tex]it means a and b are part of the interval, we use the closed brackets
B)open interval
this interval is one that does not include its endpoints
[tex](a,b)[/tex]it means a and b are not part of the interval
C) combinatios
[tex]\begin{gathered} (a,b\rbrack \\ \lbrack a,b) \end{gathered}[/tex]so, we have the interval
[tex]\lbrack-1,12)[/tex]it means -1 is part of the set and 12 is not part of the set
as -1 is part of the interval, we need the number equal or greater than -1
