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22 tháng 5 2015

A=x^4+6x^3+7x^2–6x+1=x^4+(6x^3–2x^2)+(9x^2–6x+1)
= x^4+2x^2(3x–1)+(3x–1)^2 =(x^2+3x–1)^2

chỉnh lại tí

22 tháng 5 2015

Đặt P(x)=x4+6x3+7x2- 6x+1

Đặt y=x2-1

=>y2=x4-2x2+1

P(x)=x4-2x2+1+6x3-6x+9x2

  =(x2-1)2+6x(x2-1)+9x2

Q(y)=y2+6xy+9x2

=(y+3x)2

P(x)=(x2-1+3x)2

13 tháng 9 2017

a,\(=x^3-x^2+5x^2-5x-24x+24\)

\(=x^2\left(x-1\right)+5x\left(x-1\right)-24\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2+5x-24\right)\)

\(=\left(x-1\right)\left(x^2-3x+8x-24\right)\)

\(=\left(x-1\right)\left(x\left(x-3\right)+8\left(x-3\right)\right)\)

\(=\left(x-1\right)\left(x-3\right)\left(x+8\right)\)

13 tháng 9 2017

a)=(x-3)(x-1)(x+8)

b)=(x2+3x-1)2

16 tháng 6 2017

a)\(3x^2-8x+4\)

\(=3x^2-2x-6x+4\)

\(=x\left(3x-2\right)-2\left(3x-2\right)\)

\(=\left(x-2\right)\left(3x-2\right)\)

b)\(4x^4+81\)

\(=4x^4+36x^2+81-36x^2\)

\(=\left(2x^2+9\right)^2-36x^2\)

\(=\left(2x^2-6x+9\right)\left(2x^2+6x+9\right)\)

c)\(x^8+98x^4+1\)

\(=\left(x^8+2x^4+1\right)+96x^4\)

\(=\left(x^4+1\right)^2+16x^2\left(x^4+1\right)+64x^4-16x^2\left(x^4+1\right)+32x^4\)

\(=\left(x^4+8x^2+1\right)^2-16x^2\left(x^4-2x^2+1\right)\)

\(=\left(x^4+8x^2+1\right)^2-16x^2\left(x^4-2x^2+1\right)\)

\(=\left(x^4+8x^2+1\right)^2-\left(4x^3-4x\right)^2\)

\(=\left(x^4+4x^3+8x^2-4x+1\right)\left(x^4-4x^3+8x^2+4x+1\right)\)

d)\(x^4+6x^3+7x^2-6x+1\)

\(=x^4+3x^3-x^2+3x^3+9x^2-3x-x^2-3x+1\)

\(=x^2\left(x^2+3x-1\right)+3x\left(x^2+3x-1\right)-\left(x^2+3x-1\right)\)

\(=\left(x^2+3x-1\right)\left(x^2+3x-1\right)\)\(=\left(x^2+3x-1\right)^2\)

2 tháng 6 2017

Tìm x

x3-x2-14x+24=0

<=> x3-3x2+2x2-6x-8x+24=0

<=> x2(x-3)+2x(x-3)-8(x-3)=0

<=> (x-3)(x2+2x-8)=0

<=> (x-3)(x2-2x+4x-8)=0

<=>(x-3)(x-2)(x+4)=0

<=> x-3=0 hay x-2=0 hay x+4=0

<=> x=3 hay x=2 hay x=-4

S={3;2;-4}

16 tháng 10 2018

        \(x^4+3x^2+36\)

\(=\left(x^2\right)^2+2.x^2.6+6^2-9x^2\)

\(=\left(x^2+6\right)^2-\left(3x\right)^2=\left(x^2-3x+6\right)\left(x^2+3x+6\right)\)

      \(2x^4-3x^3-7x^2+6x+8\)

\(=2x^4+2x^3-5x^3-5x^2-2x^2-2x+8x+8\)

\(=2x^3\left(x+1\right)-5x^2\left(x+1\right)-2x\left(x+1\right)+8\left(x+1\right)\)

\(=\left(x+1\right)\left(2x^3-5x^2-2x+8\right)\)

\(=\left(x+1\right)\left[2x^2\left(x-2\right)-x\left(x-2\right)-4\left(x-2\right)\right]\)

\(=\left(x+1\right)\left(x-2\right)\left(2x^2-x-4\right)\)

Chúc bạn học tốt.

19 tháng 7 2017

\(=\left(x+1\right)\left(x-2\right)\left(2x^2-x-4\right)\)

29 tháng 9 2019

a) Ta có : 6x2 - 13x + 6 = 6x2 - 9x - 4x + 6 = 3x(2x - 3) - 2(2x - 3) = (3x - 2)(2x - 3)

b) Ta có: 6x2 + 7x - 3 = 6x2 + 9x - 2x - 3 = 3x(2x + 3) - (2x + 3) = (3x - 1)(2x + 3)

29 tháng 9 2019

\(a,6x^2-13x+6\)

\(=6x^2-9x-4x+6\)

\(=3x\cdot\left(2x-3\right)-x\cdot\left(2x-3\right)\)

\(=\left(2x-3\right)\cdot\left(3x-x\right)\)

\(=\left(2x-3\right)\cdot2x\)

\(b,6x^2+7x-3\)

\(=6x^2-2x+9x-3\)

\(=2x\cdot\left(3x-1\right)+3\cdot\left(3x-1\right)\)

\(=\left(3x-1\right)\cdot\left(2x+3\right)\)