Mathématiques

Question

Bonsoir pouvez-vous m’aider 13 Factorise les expressions suivantes
a. (2x - 3)(x + 2) – 5(2x – 3)
b. (5x + 1)(3x – 5) - (x – 3)(5x + 1)
c. (3x + 2)(-5x – 7) – (3x + 2)(x + 7)
d. (5x – 8)(7x – 3) – (7x – 3)2
Merci

1 Réponse

  • bonsoir

    a. (2x - 3)(x + 2) – 5(2x – 3)

    = ( 2 x - 3 ) ( x + 2 - 5 )

    = ( 2 x - 3 ) ( x - 3 )

    b. (5x + 1)(3x – 5) - (x – 3)(5x + 1)

    =  ( 5 x + 1 ) ( 3 x - 5 - x + 3 )

    = ( 5 x + 1 ) ( 2 x - 2 )

    = 2 ( 5 x + 1 ) ( x - 1 )

    c. (3x + 2)(-5x – 7) – (3x + 2)(x + 7)

    =  ( 3 x + 2 ) ( - 5 x - 7 - x - 7 )

    = ( 3 x + 2 ) ( - 6 x - 14 )

    =  2  ( 3 x + 2 ) ( - 3 x - 7 )

    d. (5x – 8)(7x – 3) – (7x – 3)2

    = ( 7 x - 3 ) ( 5 x - 8 - 7 x + 3 )

    = ( 7 x - 3 ) ( - 2 x - 5 )

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