Cho đa thức : `P(x) x^5 – 3x^2+x^4 – 1/2x-x^5+5x^4+x^2-1` `Q(x)=x-x^9+x^2 – 5-x^3+x^6-x+3x^9+2x^6-x^3+7` Tính : Q(x) – P(x)

1 bình luận về “Cho đa thức : `P(x) x^5 – 3x^2+x^4 – 1/2x-x^5+5x^4+x^2-1` `Q(x)=x-x^9+x^2 – 5-x^3+x^6-x+3x^9+2x^6-x^3+7` Tính : Q(x) – P(x)”

1. #nqcii.

   – Rút gọn đa thức :

   P(x) = x^5 – 3x^2 + x^4 – 1/2x – x^5 + 5x^4 + x^2 – 1

   P(x) = ( x^5 – x^5 ) + ( -3x^2 + x^2 ) + ( x^4 + 5x^4 ) – 1/2x – 1

   P(x) = -2x^2 + 6x^4 – 1/2x – 1

   Q(x) = x – x^9 + x^2 – 5 – x^3 + x^6 – x + 3x^9 + 2x^6 – x^3 + 7

   Q(x) = ( x – x ) + ( -x^9 + 3x^9 ) + x^2 + ( -5 + 7 ) + ( -x^3 – x^3 ) + ( x^6 + 2x^6 )

   Q(x) = 2x^9 + x^2 + 2 – 2x^3 + 3x^6

   => Q(x) – P(x) = ( -2x^2 + 6x^4 – 1/2x – 1 ) – ( 2x^9 + x^2 – 2x^3 + 3x^6 )

   => Q(x) – P(x) = -2x^2 + 6x^4 – 1/2x – 1 – 2x^9 – x^2 + 2x^3 – 3x^6

   => Q(x) – P(x) = ( -2x^2 – x^2 ) + 6x^4 – 1/2x – 1 – 2x^9 + 2x^3 – 3x^6

   => Q(x) – P(x) = -3x^2 + 6x^4 – 1/2x – 1 – 2x^9 + 2x^3 – 3x^6

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