Вправи: 527-528

527. Виконайте дії:

1) 16 + (3а + 4)(3а – 4) = 16 + 9а² – 16 = 9а²;

2) (5m – 3)(5m + 3) – 25m² = 25m² – 9 – 25m² = –9.

528. Спростіть вираз:

1) (8x – 5)(8х + 5) + 25 = 64x² – 25 + 25 = 64х²;

2) 9m2 + (5 – 3m)(5 + 3m) = 9m² + 25 – 9m² = 25;

3) (2b – 3)(3 + 2b) – 4b² = (2b – 3)(2b + 3) – 4b² = 4b² – 9 – 4b² =

= –9;

4) (4а + 7)(7 – 4а) – 49 = (7 + 4а)(7 – 4а) – 49 = 49 – 16а² – 49 =

= –16а².