Svvvp aidee pour la 3) merci d'avance

I = 7a + 7b = 7(a+b)
J = 5x² - 2x  =  x (5x-2)
K = 20x + 5  = 5 (4x +1)
L = incomplet
M = 5(x+2)+ (3x-1) (x+2)  = (x+2) (5 +3x -1)  =(x+2) (3x + 4)
N = incomplet