2. а) х²-49 = х²-7² = (х+7)(х-7);
б) 1 - 64/81х² = 1² - (8/9х)² = (1+8/9х)(1-8/9х);
в) а^4 - 0,09 = (а²)²- 0,3² = (а²+0,3)(а²-0,3);
г) 25а^10 - 36х^14 = (5a^5)² - (6x^7)² = (5a^5 + 6x^7)(5a^5 - 6x^7);
д) 1/9х^8 - у^10 = (1/3х^4)² - (у^5)² = (1/3х^4 + у^5)(1/3х^4 - у^5);
е) 169х^4у^6z^8 - 196 = (13x²y³z^4 + 14)(13x²y³z^4 - 14);
ж) (9m²-5n²)² - (6m²+n²)² = (9m²-5n²+6m²+n²)(9m²-5n²-6m²-n²) = (15m²-4n²)(3m²-6n²) = (3m²-2n²)(5+2)(1+3) = 28(3m²-2n²);
з) (6х+у-2z)² - (x-y+z)² = (6х+у-2z + x-y+z)(6х+у-2z - x+y-z) = (7x-z)(5x+2y-3z);
Вроде так...