Explanation:
every number greater than or equal to 7.
just as the expression says.
are we taking only about integer values ?
so,
7, 8, 9, 10, ... +infinity
if we aim for radical or real values, then starting with 7 everything between these numbers.
the interval definition is
[7, +infinity)
please note the different brackets.
"[" or "]" means the interval end value is included.
"(" or ")" means the interval end value is excluded.
which is the normal thing for infinity, because infinity is only a concept and never a number. so, it cannot be included.