1)b² - 2b + 1
D = b² - 4ac = 4 - 4×1 = 0
x = -b/2a
x = 2/2 = 1,значит,
b² - 2b + 1 = ( b - 1)² = (b - 1)(b - 1)
2) (a - 2b)² - ( a + 2b)² = ( a - 2b - a - 2b)(a - 2b + a + 2b) = - 4b × 2a = - 8ab
3) y² + 2y + 1= ( y + 1)²
При y = 999:
( y + 1)² = (999 + 1)² = 1000² = 1000000
4) ( a - b)² + 8ab = a² - 2ab + b² + 8ab = a² + 6ab + b²