A=2(x-3) B=5(3x+2) C=4x(2x+1) D=-2(5x-3)

A = 2x - 6
B = 15x + 10
C = 8x² + 4x
D = -10x + 6

A = 2 (x - 3)
A = 2 X x + 2 X (- 3)
A = 2x - 6

B = 5 (3x + 2)
B = 5 X 3x + 5 X 2
B = 15x + 10

C = 4x (2x + 1)
C = 4x X 2x + 4x X 1
C = 8x² + 4x

D = - 2 (5x - 3)
D = - 2 X 5x - 2 X (- 3)
D = - 10x + 6

Les "X" majuscules désignent "fois".
Les "x" minuscules désignent la lettre.