Question

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规定一种新运算：a*b=ab+a-b，求a*b+（b-a）*2

Answer 1

a*b+（b-a）*2
=ab+a-b+2(b-a)+b-a-2
=ab+a-b+2b-2a+b-a-2
=ab-2a+2b-2

Answer 2

a*b+(b-a)*2
=ab+a-b+2(b-a)+b-a-b
=ab+a-b+2b-2a+b-a-b
=ab-2a+b

Answer 3

a*b+（b-a）*2
=ab+a-b+2(b-a)+b-a-2
=ab+a-b+2b-2a+b-a-2
=ab-2a+2b-2

Answer 4

a*b+(b-a)*2
=ab+a-b+2*(b-a)+b-a-2
=ab-2a+2b-2