1) x² – 6x + 9 – y² 2) 4x² – 9 3) (x² – 25) + x + 5 4) 3x² – 4x + 1

2 bình luận về “1) x² – 6x + 9 – y² 2) 4x² – 9 3) (x² – 25) + x + 5 4) 3x² – 4x + 1”

1. a)x^2-6x+9-y^2

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

   b)4x^2-9

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

   c)x^2-25+x+5

   =(x-5)(x+5)+(x+5)

   =(x-5+1)(x+5)=(x-4)(x+5)

   d)3x^2-4x+1

   =3x^2-3x-x+1

   =3x (x-1)-(x-1)=(3x-1)(x-1)

   Trả lời
2. 1)

   x^2-6x+9-y^2

   = x^2-2.x.3+3^2-y^2

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

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

   2)

   4x^2-9

   = (2x)^2-3^2

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

   3)

   (x^2-25)+x+5

   = (x+5)(x-5)+(x+5)

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

   = (x+5)(x-4)

   4)

   3x^2-4x+1

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

   = x(3x-1)-(3x-1)

   = (3x-1)(x-1)

   $#<33$

   Trả lời