Let's solve the system of equations:
b + c = - 55
b - c = 17
Step 1: Let's isolate b on the first equation:
b + c = - 55
b = - 55 - c
Step 2: Let's solve for c on the second equation, substituting b:
b - c = 17
-55 - c - c = 17
-55 - 2c = 17
Adding 55 at both sides:
-2c - 55 + 55 = 17 + 55
-2c = 72
Dividing by - 2 at both sides:
-2c/-2 = 72/-2
c = -36
Step 3: Let's solve for b on the first equation, susbtituting c:
b + c = - 55
b + (-36) = - 55
b - 36 = - 55
Adding 36 at both sides:
b - 36 + 36 = - 55 + 36
I think you are ready to finish and calculate the value for b.