Answer:
c = -a - b + 180
Step-by-step explanation:
Isolate the c. Note the equal sign, what you do to one side, you do to the other. Subtract a and b from both sides
a (-a) + b (-b) + c = 180 (-a) (-b)
c = 180 - a - b
c = -a - b + 180 is your answer
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