comment developper et reduire les exepressions suivantes A=5x(x-1) B=(x-1)(x+4) C= (2x+3)(x-1)-(4x+14)(x-3)

A = 5x (x - 1)
A = 5x * x + 5x * (- 1)
A = 5x² - 5x

B = (x - 1) (x + 4)
B = x * x + x * 4 - 1 * x - 1 * 4
B = x² + 4x - x - 4
B = x² + 3x - 4

C = (2x + 3) (x - 1) - (4x + 14) (x - 3)
C = 2x * x + 2x * (- 1) + 3 * x + 3 * (- 1) - [4x * x + 4x * (- 3) + 14 * x + 14 * (- 3)]
C = 2x² - 2x + 3x - 3 - (4x² - 12x + 14x - 42)
C = 2x² - 2x + 3x - 3 - 4x² + 12x - 14x + 42
C = - 2x² - x + 39

Les * désignent "fois".