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\(A=x^{10}-14x^9-x^9+14x^8+x^8-14x^7-x^7...-x+14+1\)
\(A=x^9\left(x-14\right)-x^8\left(x-14\right)+x^7\left(x-14\right)-...-x\left(x-14\right)+1\)
\(A=1\) (Do x=14)
Ta có x=14 suy ra x+1=15
Do đó thay x+1 vào H(x), ta được:
H(14)= x10 - (x+1)x9 +(x+1)x8-(x+1)x7+...+ (x+1)x2 - (x+1)x + x+1
H(14)= x^10 - x^10 -x^9 +x^8- x^8-x^7 +....+ x^3 +x^2 -x^2-x+x +1
Hay H(14)=1
Đặt Q(x) = x9 - x8 + x7 - ... + x - 1 thì (x + 1) * Q(x) = (x + 1) * (x9 - x8 + x7 - ... + x - 1) = x10 - 1 \(\Rightarrow\left(14+1\right)\cdot Q\left(14\right)=14^{10}-1\)
Dễ thấy: H(x) = x10 - 15* Q(x) \(\Rightarrow H\left(14\right)=14^{10}-\left(14^{10}-1\right)=1\)
Xin cậu !
a: \(=\dfrac{x^4+15x+7}{x^4+15x+7}\cdot\dfrac{x}{14x^2+1}\cdot\dfrac{4x^3+4}{2x^3+2}=\dfrac{2x}{14x^2+1}\)
b: \(=\dfrac{x^7+3x^2+2}{x^7+3x^2+2}\cdot\dfrac{x^2+x+1}{x^3-1}\cdot\dfrac{3x}{x+1}\)
\(=\dfrac{1}{x-1}\cdot\dfrac{3x}{x+1}=\dfrac{3x}{x^2-1}\)
\(6x^5+15x^4+20x^3+15x^2+6x+1 \)
\(=6x^5+3x^4+12x^4+6x^3+14x^3+7x^2+8x^2+4x+2x+1\)
\(=\left(2x+1\right)\left(3x^4+6x^3+7x^2+4x+1\right)\)
\(=\left(2x+1\right)\left(3x^4+3x^3+3x^2+3x^3+3x^2+x^2+x+1\right)\)
\(=\left(2x+1\right)\left(x^2+x+1\right)\left(3x^2+3x+1\right)\)
a, = [(x-2).(x+1)]^2+(x-2)^2
= (x-2)^2.(x+1)^2+(x-2)^2
= (x-2)^2.[(x+1)^2+1]
= (x-2)^2.(x^2+2x+2)
Tk mk nha
b) \(6x^5+15x^4+20x^3+15x^2+6x+1\)
\(=6x^5+3x^4+12x^4+6x^3+14x^3+7x^2+8x^2+4x+2x+1\)
\(=\left(2x+1\right)\left(3x^4+6x^3+7x^2+4x+1\right)\)
\(=\left(2x+1\right)\left(3x^4+3x^3+3x^2+3x^3+3x^2+3x+x^2+x+1\right)\)
\(=\left(2x+1\right)\left(x^2+x+1\right)\left(3x^2+3x+1\right)\)
a/ \(\dfrac{3x^2y+5}{15x^3y^4}+\dfrac{3x^2y-5}{15x^3y^4}=\dfrac{3x^2y+5+3x^2y-5}{15x^3y^4}=\dfrac{6x^2y}{15x^3y^4}=\dfrac{2}{5xy^3}\)
b/ \(\dfrac{2x^2-x}{x^2+x+1}+\dfrac{x^3-2x^2+x+1}{x^2+x+1}=\dfrac{2x^2-x+x^3-2x^2+x+1}{x^2+x+1}=\dfrac{x^3+1}{x^2+x+1}\)