Question

reduza (x-y)² + (x+y)²
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Answer 1

$(xy) {}^{2} - x(x - 2y) = \\ x {}^{2} - 2xy + y {}^{2} - x {}^{2} + 2xy = \\ x { }^{2} - x {}^{2} - 2xy + 2xy + y {}^{2} = 0 - 0 + y {}^{2} =y {}^{2}$