Réponse:
EXERCICE:1
A=3(4x+7)+4(2x-9)
=3×4x+3×7+4×2x+4×(-9)
=12x+21+8x+(-36)
=12x+8x+21+(-36)=20x+(-15)
B=7×(2x-5)-x(2x-5)
=7×2x+7×-5+(-x×2x-x×(-5)
=14x-35x-2x²+5x
=2x²+14x+5x-35
=2x²+19x-35
C=(2x+5)(3x+7)
=2x×3x+2x×7+5×3x+5×7
=6x²+14x+15x+35
=6x²+29x+35
D=(2x-5)(3x-2)
=2x×3x+2x×(-2)-5×3x+(-5)×(-2)
=6x²+x-15x+10
=6x²-14x+10
EXERCICE:3
H=(x+5)²
=x²+2(x×5)+5²
=x²+10x+25
I=(4x+6)²
=(4x)²+2(4x×6)+6²
=16x²+48x+36
J=(x-5)²
=x²-2(x×5)+5²
=x²-10x+25
