Answer:
a - 8b + 13c
Explanation:
a - (4b -( a - 5b + c + 3c -(a - b - 9c)))
a - (4b - (-5b + c + 3c + b + 9c)))
a - (4b - (-4b + 13c)))
a - (4b + 4b - 13c)
a- (8b - 13c)
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