Explications étape par étape:
A = (x - 4) x (3x - 7)
= (x X 3x) + ( -4 × -7)
= 3x² - 28
B = (-4x + 8)²
= (-4x X -4x) + (8 x 8)
= -16x² + 64
C = -5x X (-6x +9)
= (-5x X -6x) + (-5x X 9)
=30x² - 45
