Exercice 7 :
A = 8x + 12y
A = 4 * 2 * x + 4 * 3 * y
A = 4 (2x + 3y)
B = 49a - 56b
B = 7 * 7 * a - 7 * 8 * b
B = 7 (7a - 8b)
C = 24x + 30y - 18z
C = 6 * 4 * x + 6 * 5 * y - 6 * 3 * z
C = 6 (4x + 5y - 3z)
D = 15xy + 30xz
D = 15 * x * y + 15 * x * 2 * z
D = 15x (y + 2z)
E = 2x² + 8x
E = 2 * x * x + 2 * x * 4
E = 2x (x + 4)
F = 25x²y - 15xy²
F = 5 * 5 * x * y * x - 5 * x * y * y * 3
F = 5xy (5x - 3y)