Разложите на множители:

1) 4 а^2-b^2-2a+b

2) y^2 (2y-5) - 8y+20

3) a^2-b^2+2 (a+b) ^2

1) = 4 а² - b² - 2a + b = (4a² - b²) - (2a - b) = (2a - b) (2a + b) - (2a - b) =

= (2a - b) (2a + b - 1)

2) y² (2y - 5) - 4 (2y - 5) = (2y - 5) (y² - 4) = (2y - 5) (y - 2) (y + 2)

3) (a - b) (a + b) + 2 (a + b) ² = (a + b) (a - b+2 (a + b)) = (a + b) (a - b + 2a + 2b) =

= (a + b) (3a + b)