Sagot :
bonjour,
exo 1:
A=3(4x+7) +4(2x-9)
A=3×4x+3×7+4×2x+4×(-9)
A= 12x+21+8x-36
A= 20x-15
B=7x(2x-5) -x(2x-5)
B=7x×2x+7x×(-5) -x×2x-x×(-5)
B= 14x²-35x-2x²+5x
B= 12x²-30x
C=(2x+5) (3x+7)
C= 2x×3x+2x×7+5×3x+5×7
C= 6x²+14x+15x+35
C= 6x²+29x+35
D=(2x-5) (3x-2)
D= 2x×3x+2x×(-2) -5×3x-5×(-2)
D= 6x²-4x-15x+10
D= 6x²-19x+10
exo 2:
E=(2x+3) (5x-8) -(2x-4) (5x-1)
E= 2x×5x+2x×(-8) +3×5x+3×(-8) -2x×5x-2x×(-1) -4×5x-4×(-1)
E= 10x²-16x+15x-24-10x²+2x-20x+4
E= -19x-20
F=(5x-2) (5x-8) -(3x-5) (x+7)
F= 5x×5x+5x×(-8) -2×5x-2×(-8) -3x×x-3x×7-5×x-5×7
F= 25x²-40x-10x+16-3x²-21x-5x-35
F= 22x²-76x-19
G=2(x+7) (3-2x) +(5x-2) (4x+1)
G= 2× x×3+x×(-2x) +7×3+7×(-2x) +5x×4x+5x×1-2×4x-2×1
G= 6x-2x²+21-14x+20x²+5x-8x-2
G= 18x²-11x+19
exo 3:
H= (x+5) ²
H= x²+2×x×5+5²
H= x²+10x+25
I=(4x+6) ²
I= (4x) ²+2×4x×6+6²
I= 16x² +48x+36
J=(x-5) ²
J= x²-2×x×5+5²
J= x²-10x+25
K=(3x-7) ²
K= (3x) ²-2×3x×7+7²
K= 9x²-42x+49
L= (y+3) (y-3)
L= y²-3²
L= y²-9
M=(2x+5) (2x-5)
M= (2x) ²-5²
M= 4x²-25
voilà je n'ai pas le temps de faire la suite mais j'espère t'avoir aidé