Cho A= 6x( 6x + 3) – ( 6x + 5) ² B= ( x + 5)( x – 4) – x(x-2) a) Thu gọn A,B b) Tìm x để A > B

1 bình luận về “Cho A= 6x( 6x + 3) – ( 6x + 5) ² B= ( x + 5)( x – 4) – x(x-2) a) Thu gọn A,B b) Tìm x để A > B”

1. a)

   A=6x( 6x + 3) – ( 6x + 5)^2

   =36x^2+18x – ( 36x^2+60x+25)

   =-42x-25

   B=( x + 5)( x – 4) – x(x-2)

   =x^2-4x+5x-20-x^2+2x

   =3x-20

   b)

   A>B<=>-42x-25> 3x-20

   <=>-42x-3x > -20+25

   <=>-45x > 5

   <=>x < -1/9

   Vậy x< -1/9

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