7 - (c + 18) > 0
-1 (c + [11])
~Now multiply each of the sides by -1~
c + 11 < 0
~Then , subtract 11 from each of the sides that you're working with~
c < -11
~Lastly, "c" becomes a negative~
-c - 11.0 > 0
Therefore your answer would have to be:
c < -11