1) a² + 6a - b² + 4b + 5 = a² + 6a - b² + 4b + 9 - 4 = (a² + 6a + 9) - (b² - 4b + 4) = (a + 3)² - (b - 2)² = ( a + 3 - b + 2)(a + 3 + b - 2) = (a - b + 5)(a + b + 1)
2) 3x² - 4xy + y² + 4x - 4 = 4x² - x² - 4xy + y² + 4x - 4 = (4x² - 4xy + y²) -
= (x² - 4x + 4) = (2x - y)² - (x - 2)² = (2x - y - x + 2)(2x - y + x - 2) =
= (x - y + 2)(3x - y - 2)
1) a² + 6a - b² + 4b + 5 = a² + 6a - b² + 4b + 9 - 4 = (a² + 6a + 9) - (b² - 4b + 4) = (a + 3)² - (b - 2)² = ( a + 3 - b + 2)(a + 3 + b - 2) = (a - b + 5)(a + b + 1)
2) 3x² - 4xy + y² + 4x - 4 = 4x² - x² - 4xy + y² + 4x - 4 = (4x² - 4xy + y²) -
= (x² - 4x + 4) = (2x - y)² - (x - 2)² = (2x - y - x + 2)(2x - y + x - 2) =
= (x - y + 2)(3x - y - 2)