11c+21=-34

11c+21=-34

11c+21-21=-34-21

11c+21-21=-55

11c=-55

11c=-55

c=-11

Answer is -11

You are right until the very last step Professor!  If 11c = -55 then c = -5 

hi Professor,  It is great that you answered this question.  I love people to get involved.

Please edit your last step to make it correct, I am reluctant to give you points until it is fixed.