Given x + y = 2, xy = - 2, then the value of (1-x) (1-y) is () A. -1B. 1C. 5D. -3
∵ x + y = 2, xy = - 2, ∵ (1-x) (1-y) = 1-y-x + xy = 1 - (x + y) + xy = 1-2-2 = - 3
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