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Carla Vista Industries incurs unit costs of $7 ( $4 variable and $3 fixed) in making an assembly part for its finished product. A supplier offers to make 16,800 of the assembly part at $5 per unit. If the offer is accepted, Carla Vista will save all variable costs but no fixed costs. Prepare an analysis showing the total cost saving, if any, that Carla Vista will realize by buying the part. (Enter negotive amounts using either a negative sign preceding the number e.g. -45 or parentheses e. 8 . (45).) The decision should be to the part