Вправи 201 - 342 » 279

279. Доведіть тотожність а–8 – b–8 = (а–4)2 – (b–4)2 = (а–4 – b–4)(a–4 + b–4) = ((а–2)2 – (b–2)2)(а–4 + b–4) = (а–2 – b–2)(а–2 + b–2)(а–4 + b–4) = ((а–1)2 – (b–1)2)(a–2 + b–2)(а–4 + b–4) = (а–1 – b–1)(a–1 + b–1)(а–2 + b–2)(а–4 + b–4).