Bonjour,
F=(7x− 3)(7x+3)- (2x+5) ²
= 49x² -9 - ( 4x² +20x +25)
= 49x² -9 - 4x² -20x -25
= 45x² -20x -34
G=(2x-1)²- (2x - 1)(x-6)
= 4x² -4x + 1 -( 2x² -12x -x +6)
= 4x² -4x + 1 - 2x² +12x +x -6
= 2x² +9x -5
J= (4x-1)²- 3x (3x-2)
= 16x² -8x +1 -9x² +6x
= 7x² -2x +1
H=(4x+5)²-7(4x+5)
= 16x² +40x +25 - 28x -35
= 16x² +12x-10
I= (3x - 5)(2x-1)-(3x - 5)²
= 6x² -3x -10x +5 -( 9x² -30x +25)
= 6x² -3x -10x +5 - 9x² +30x -25
= -3x²+17x- 20