1) (4x^2-4x+1)-(x+1) 2) X^3+1-x^2-x 3) -4x^2+12xy+25-9y^2 4) X^3-27-3x^2+9x 5) X^3-x+y^3-y -6) 4x^2-1+4x

1 bình luận về “1) (4x^2-4x+1)-(x+1) 2) X^3+1-x^2-x 3) -4x^2+12xy+25-9y^2 4) X^3-27-3x^2+9x 5) X^3-x+y^3-y -6) 4x^2-1+4x”

1. 1) (4x^2 – 4x +1)-(x+1)

   =  4x^2 – 4x +1 – x-1

   = 4x^2 -5x

   = x(4x-5)

   2) x^3 +1 -x^2 -x

   = (x^3 -x^2)-(x-1)

   = x^2(x-1)-(x-1)

   = (x-1)(x^2 -1)

   = (x-1)(x+1)(x-1)

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

   3) -4x^2 + 12xy + 25 -9y^2

   = 25-(4x^2 – 12xy + 9y^2)

   =5^2 – (2x-3y)^2

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

   4) x^3 -27 – 3x^2 +9x

   = (x^3 – 3x^2)-(27 -9x)

   = x^2( x-3)-9(3-x)

   = x^2(x-3)+9(x-3)

   = (x^2 +9)(x-3)

   5) x^3 – x + y^3 -y

   = (x^3 + y^3)-(x+y)

   = (x+y)(x^2 – xy + y^2) -(x+y)

   = (x+y)(x^2 -xy + y^2 -1)

   6) -4x^2 -1 +4x

   = -(4x^2- 4x +1)

   = -(2x-1)^2

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