Answer: c=-1,b=5,a=-5
Step-by-step explanation: If c=-1, substitute it into the second equation first. The second equation becomes -2b-1=-11, simplify it becomes -2b=-10, divide by 2 it becomes -b=-5, so b=5. Then you substitute b and c into the first equation. The first equation becomes a+5+-(-4)=4, simplify it becomes a+5+4=4, Simplify again it becomes a=-5.