Question 1181406
You are on the right track.  You have 3 equations and 3 unknowns. There are
several methods for solving. For example, you can use the substitution method
and solve the 1st equation for c: c = b - a
Substitute the value for c in the other two equations. Then solve the 2nd
equation for b: b = -2a
Now substitute this value in the 3rd equation: -3a = 6 -> a = -2
Thus, b = 4 and c = 6