Answers

2016-06-21T15:18:33+08:00
= -(2x-y-(3x-4x-y+3-7))
= -(2x-y-3x+4x+y-3+7)
= -2x+y+3y-4x-y+3-7
= -2x-4x+y+3y+3-7
= -6x+4y-5









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