Differential Analysis In each of four independent cases, the amount of differential revenue or differential cost is as follows (parentheses indicate decreases): 1 2 3 4 Increases (decreases) in: Revenue $18,000 $0 ? ? ? ? $(12,000) $0 Costs For each case, determine the missing amount that would be necessary for the net differential amount to be: a. $8,000 Use a negative signs with answers to reflect decreases. 1 2 3 4 Increases (decreases) in: Revenue $18,000 $0 $ $ Costs $ $ $(12,000) $0 b. ($4,000) Use a negative signs with answers to reflect decreases. 1 2 3 4 Increases (decreases) in: Revenue $18,000 $0 $ $ Costs $ $ $(12,000) $0