Bonsoir,

F = (5 + 4x)(3x - 2) - (2x + 1)²

F = 15x - 10 + 12x² - 8x - [(2x)² + 2 × 2x × 1 + 1²]

F = 12x² + 7x - 10 - (4x² + 4x + 1)

F = 12x² + 7x - 10 - 4x² - 4x - 1

F = 8x² + 3x - 11

G = 2x(2x + 1) + (3x + 2)(x + 1)

G = 4x² + 2x + 3x² + 3x + 2x + 2

G = 7x² + 7x + 2

H = x(x + 1)(x - 3)

H = x[x² - 3x + x - 3]

H = x[x² - 2x - 3]

H = x³ - 2x² - 3x

I = x² - (3 + x)²

I = x² - (3² + 2 × 3 × x + x²)

I = x² - (9 + 6x + x²)

I = x² - 9 - 6x - x²

I = -6x - 9

J = (2x + 1)² + (2 + x)²

J = (2x)² + 2 × 2x × 1 + 1² + 2² + 2 × 2 × x + x²

J = 4x² + 4x + 1 + 4 + 4x + x²

J = 5x² + 8x + 5