Bonjour
A = (9x - 7)²
A = 81x² - 126 + 49
B = (x + 9) (11 - 5x)
B = 11x - 5x² + 99 - 45x
B = - 5x² + 11x - 45x + 99
B = - 5x² - 34x + 99
C = (2x - 3) (2x + 3)
C = 4x² - 9
D = (11 + 8x)²
D = 121 + 176x + 64x²
E = (x + 1)² + 7x (2 - x)
E = x² + 2x + 1 + 14x - 7x²
E = x² - 7x² + 2x + 14x + 1
E = - 6x² + 16x + 1
F = (x + 3) (2x - 1) - 3x (2x + 5)
F = 2x² - x + 6x - 3 - 6x² - 15x
F = 2x² - 6x² - x - 15x + 6x - 3
F = - 4x² - 10x - 3
G = (4t + 1) (4t - 1) - (3t + 2)²
G = 16t² - 1 - (9t² + 12t + 4)
G = 16t² - 1 - 9t² - 12t - 4
G = 16t² - 9t² - 12t - 1 - 4
G = 7t² - 12t - 5
H = 2 (s + 5) (s - 5) + (4 s + 3)²
H = 2 (s² - 25) + 16s² + 24s + 9
H = 2s² - 50 + 16s² + 24s + 9
H = 2s² + 16s² + 24s - 50 + 9
H = 18s² + 24s - 41
I = (3x + 4)² - (1 - 2x) (6 + x)
I = 9x² + 24x + 16 - (6 + x - 12x - 2x²)
I = 9x² + 24x - 16 - 6 - x + 12x + 2x²
I = 9x² + 2x² + 24x + 12x - x - 16 - 6
I = 11x² + 35x - 22.