2. When proving a statement of the form "S ," one ef- fective strategy is to use proof by contradiction. Specit- ically, begin with the assumption that there is some ele- ment xe S, and argue that...

Could you answer 12. d)

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Extracted text: 2. When proving a statement of the form "S ," one ef- fective strategy is to use proof by contradiction. Specit- ically, begin with the assumption that there is some ele- ment xe S, and argue that some absurdity results. Try this type of reasoning on the following statements to be proven: (a) (2k+1: ke N} n (4k: ke N} = Ø (b) ((3k+1: ke Z) n (6k+5: ke Z}) = Ø


Extracted text: (c) (1(x, y) e R xR : -2x-3 y} n((x, y)e 6 y}) = 0 R x R: x (d) If A C B, then A n B' =0. for the follor.