Bonsoir,

J = 49 - x²

J = - (x - 7) (x + 7)

K = 7 (4x + 1) - (2x + 9) (4x + 1)

K = (4x + 1) (2x + 9 - 7)

K = (4x + 1) (2x + 2)

K = - 2(x + 1) (4x + 1)

L = 100x² - 150x + 25

L = 25 (4x² - 6x + 1)

M = 16x - 56y

M = 8 (2x - 7y)

N = 9a² + 24a + 16

N = (3a + 4)².