Вправи: 467

467. Спрости вираз.

a) (x – y)^–2(x² – y²) = x2- y2(x-y)2 = x-y(x+y)x-y(x-y) = x+yx-y;

б) (a^–3 – b^–3)^–1 – (a^–3 + b^–3)^–1 = (1a3 – 1b3)^–1 – (1a3 + 1b3)^–1 = (b3- a3a3b3)^–1 – (b3+ a3a3b3)^–1 = a3b3b3- a3 – a3b3b3+ a3 = a3b3(b3+ a3- b3+ a3)(b3- a3)(b3+ a3) = a3b3 • 2a3b6- a6 = 2a6b3b6- a3.