it can be shortened to x > -7 because every value for x that satisfies that must also satisfy x ≥ -9. in other words, any x that is greater than (-7) is already either greater than or equal to (-9).

worth noting: every number greater than (-7) is strictly greater than (-9), but "greater than OR equal to" only requires the number to be one of "greater than" / "equal to". so, it's ok that we're not worrying about (-9) itself since it isn't greater than (-7) anyway.