Given: |ab| = ab and |a| = -a

Question: |b-4| + |ab-b| = ?

**** Looking at |ab| = ab tells us that a and b are either both positive or negative

**** Looking at |a| = -a tells us that a must be negative

**** Combine two observations: a and b are both negative values

Let a=-1 and b=-1

|b-4| + |ab-b| = |-1-4| + |1-(-1)| = 7

Test a) ab-4 = (-1)(-1)-4 = -3

Test b) 2b-ab-4 = (2)(-1) - (1) - 4 = -7

Test c) ab+4 = 1 + 4 = 5

Test d) ab-2b+4 = 1-2(-1)+4=7 BINGO!

Answer: D

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