1)
x² - 3x + 2 =
= x² - x - 2x + 2 =
= (x² - x) - (2x - 2) =
= x·(x - 1) - 2·(x - 1) =
= (x - 1)·(x - 2)
2)
2x² + 3x + 1 =
= 2x² + 2x + x + 1 =
= (2x² + 2x) + (x + 1) =
= 2x·(x + 1) + 1·(x + 1) =
= (x + 1)·(2x + 1)
3)
2x² + 7x - 4 =
= 2x² + 8x - x - 4 =
= (2x² + 8x) - (x + 4) =
= 2x·(x + 4) - 1·(x + 4) =
= (x + 4)·(2x - 1)
