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

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

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

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

   =-2x^2+6x^4-1/2x-1

   =6x^4-2x^2-1/2x+1

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

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

   =2x^9+x^2-6x^3+3x^6+7

   =2x^9+3x^6-6x^3+x^2+7

   =>P(x)+Q(x)=(6x^4-2x^2-1/2x+1)+(2x^9+3x^6-6x^3+x^2+7)

   =6x^4-2x^2-1/2x+1+2x^9+3x^6-6x^3+x^2+7

   =6x^4-(2x^2-x^2)-1/2x+(1+7)+2x^9-6x^3

   =6x^4-x^2-1/2x+8+2x^9-6x^3

   Vậy P(x)+Q(x)=6x^4-x^2-1/2x+8+2x^9-6x^3

   \color{green}{\text{~Bachira~}}

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2. Giải đáp:

    

   Lời giải và giải thích chi tiết:

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

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

   P(x) = 6x^4 – 1/2x + -2x^2 – 1

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

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

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

   P(x) + Q(x) = 6x^4 – 1/2x + -2x^2 – 1 + 2x^9 + x^2 – 6x^3 +x^6 + 7 +2x^5  

   P(x) + Q(x) = 6x^4 – 1/2x + ( -2x^2 + x^2 ) + ( – 1 + 7 ) + 2x^9 – 6x^3 + x^6 +2x^5

   P(x) + Q(x) = 6x^4 – 1/2x -x^2 +6+2x^9 – 6x^3 + x^6- 2x^5

    

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