Rút gọn `(x^3 + 3x – 4)/(x^2 – 3x +2)`

2 bình luận về “Rút gọn `(x^3 + 3x – 4)/(x^2 – 3x +2)`”

1. (x^3+3x-4)/(x^2-3x+2) (ĐK : x \ne 1 ; 2)

   = [(x-1)(x^2+x+4)]/[(x-1)(x-2)

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

   x^3 + 3x – 4

   = x^3 – x^2 +x^2 + 4x -x -4

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

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

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

   Trả lời
2. (x^3+3x-4)/(x^2-3x+2)

   =(x^3-x^2+x^2-x+4x-4)/(x^2-x-2x+2)

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

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

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

   Trả lời