Bonjour,
A = (7x + 3)(x + 5)=
7x² +35x +3x +15=
7x² +38x +15
B = (5 - 2x)(3x - 6)=
15x -30 -6x² +12x=
-6x² +27x -30
C = (3x + 1)(-5x + 3) =
-15x² +9x -5x +3=
-15x² +4x +3
D = (7x - 2)2=
14x -4
E = (-4x - 2)(-x + 8)=
4x² -32x +2x -16=
4x² -30x -16
F = 4(2x - 1)(-x + 3)=
(8x -4) ( -x+3)=
-8x² +24x +4x -12=
-8x² =28x -12