Je comprend pas aider moi svp exercice 64

Bonsoir,

64)

A = (2x - 6) (4 - x) + 3x²

A = 8x - 2x² - 24 + 6x + 3x²

A = - 2x² + 3x² + 8x + 6x - 24

A = x² + 14x - 24

B = (x + 5)² - (1 - 4x)

B = x² + 10x + 25 - 1 + 4x

B = x² + 10x + 4x + 25 - 1

B = x² + 14x + 24

A = B.