Réponse:
Bonjour.
1)
(3x+2)(5x+4)= 3x×(5x+4)+2×(5x+4)
= 3x×5x+3x×4+2×5x+2×4
=15x au carré + 12x+10x+8
=15x au carré +22x+8
2)
(5x+3)(2x+8)= 5x×(2x+8)+3×(2x+8)
= 5x×2x+5x×8+3×2x+3×8
=10x au carré +40x+6x+24
=10x au carré +46x+24
