Réponse:
[tex]a = 5x \times (9x + 8) \\ = 5x \times 9x + 5x \times 8 \\ = 45 {x}^{2} + 40x[/tex]
[tex]b = 7 \times (4x - 5) \\ = 7 \times 4x - 7 \times 5 \\ = 28x - 35[/tex]
c)(8x - 3)× 5x
=5x × 8x - 5x × 3
=40x^2-15x
[tex]d) - 2 \times ( - 3 - 6x) \\ = - 2 \times ( - 3) - 2 \times ( - 6x) \\ = 6 + 12x[/tex]
voilà j'espère t'avoir aidé
