thu gon bieu thuc sau a) x (2x^2-3)-x^2 (5x+1)+x^2 b)3x (x-2)-5x (1-x)-8 (x^2-3) c)(x+3) (x^2-3x+9)-(54+x^3) d) (2x+y) (4x^2-2xy+y^2)-(4x^2+2xy+y^2)

0 bình luận về “thu gon bieu thuc sau a) x (2x^2-3)-x^2 (5x+1)+x^2 b)3x (x-2)-5x (1-x)-8 (x^2-3) c)(x+3) (x^2-3x+9)-(54+x^3) d) (2x+y) (4x^2-2xy+y^2)-(4x^2+2xy+y^2)”

1. a) x ( $2x^{2}$ – 3 ) – $2x^{2}$ ( 5x + 1 ) + $2x^{2}$

   = $2x^{3}$ – 3x – $2x^{2}$ – $10x^{3}$ + $2x^{2}$ + $2x^{2}$

   = – $8x^{3}$ – 3x + $2x^{2}$

   b) 3x ( x – 2 )-5x ( 1 – x )-8 ($x^{2}$ – 3)

   = $3x^{2}$ – 6x -5x -$5x^{2}$ – $8x^{2}$ + 24

   = – $10x^{2}$ -11x + 24

   c) (x+3) ($x^{2}$ -3x+9)-(54+$x^{3}$ )

   = $x^{3}$ -$3x^{2}$ + 9x  + $3x^{2}$ – 9x + 27 – 54 – $x^{3}$

   = 27

   d)( 2x + y )( $4x^{2}$ – 2xy + $y^{2}$)-( $4x^{2}$ +2xy+$y^{2}$ ) 

   = $8x^{3}$ – $4x^{2}$y + $2xy^{2}$ + $4x^{2}$y – $4x^{2}$ – 2xy – $y^{2}$

   = $8x^{3}$ + $2xy^{2}$ – $4x^{2}$ – 2xy – $y^{2}$ 

    

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