Вправи: 280

280. Спростіть вираз:

1) (а^–4 + 3)(а^–4 – 3) – (а^–4 + 2)² = (а^–4)² – З² – ((а^–4)² + 4а^–4 + 4) = а^–8 – 9 – а^–8 – 4а^–4 – 4 = –4a^–4 – 13;

2) m-2- m-2m-1+ n-1 = m-1- n-1(m-1+ n-1)m-1+ n-1 = m^–1 – n^–1;

3) 2x-2+ y-23x-2- 3x-1y-1 – x-1x-1- y-1 = 2x-2+ y-23x-1(x-1- y-1) – x-1\3x-1x-1- y-1 = 2x-2+ y-2- 3x-23x-1(x-1- y-1) = y-2- x-23x-1(x-1- y-1)=–y-1- x-1(y-1+ x-1)3x-1(x-1- y-1) = –(y-1+ x-1)3x-1;

4) a-5+ b-5a-6 : a-3b-5+ a-8a-4 = a-5+ b-5 • a-4a-6 • a-3(b-5+ a-5) = a-4a-9 = a⁵.