Câu 1 : a ) ( 2x – 1 ) ( 3x + 2 ) ( 3 – x ) b ) ( x + 3 ) ( x ² + 3x – 5 )

0 bình luận về “Câu 1 : a ) ( 2x – 1 ) ( 3x + 2 ) ( 3 – x ) b ) ( x + 3 ) ( x ² + 3x – 5 )”

1. a ) ( 2x – 1 ) ( 3x + 2 ) ( 3 – x )

   = ( 5x² + 4x – 3x + 2 ) ( 3 – x ) 

   = 15x² + 7x – 6x + 5 – 5x³ + 4x² – 3x² + 2x

   b ) ( x + 3 ) ( x ² + 3x – 5 )

   = x³ + 3x² – 5x + 3x² + 6x – 15 

    

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2. Đáp án:

   a, $(2x-1)(3x+2)(3-x)$

   $=(6x^2+4x-3x-2)(3-x)$

   $=(6x^2+x-2)(3-x)$

   $=18x^2-6x^3+3x-x^2-6+2x$

   $=-6x^3+17x^2+3x-6$

   b, $(x+3)(x^2+3x-5)$

   $=x^3+3x^2-5x+3x^2+9x-15$

   $=x^3+6x^2+4x-15$

    

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