L'énoncé a été complété en commentaires!
X(3x-2)+7x^2
=(x×3x)-(x×2)+7x^2
=3x^2-2x+7x^2
=10x^2-2x
4x^2-3(5-2x)
=4x^2-(3×5)+(3×2x)
=4x^2+6x-15
(4x-2)(3+5x)
=(4x×3)+(4x×5x)-(2×3)-(2×5x)
=12x+20x^2-6-10x
=20x^2+2x-6
2-(3-x)(2x-1)
=2-(3×2x)+(3×1)+(x×2x)-(x×1)
=2-6x+3+2x^2-x
=2x^2-7x+5
