Ответ:

номер 1:

33 × 27 = 30 × 27 + 3×27 = 810 + 81 = 891

89 × 91 = 89 × 90 + 89 × 1 = 8010 + 89 = 8099

номер 2:

1) 64n^2 - m2

2) (4k^5 - 0.7c^6)^2

номер 3:

55 × 62 = 55×60 + 55×2 = 3300 + 110 = 3410

(x + y) (x - y) = x^2 - y^2