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Update 2: Ten more questions: .knowledge.yahoo/question/question? qid=700908280030 1

q 1 a(x-y)+b(x-y)=(x-y)(a+b)Q2 x(a-b)+y(b-a)= x(a-b)-y(a-b)=(a-b)(x-y)Q3(a-b)3-(a-b)2 =(a-b)[(a-b)- 1]=(a-b)(a-b)- 1)Q4(2x-y)(a+ 1)