\(x^4+6x^3+7x^2-6x-8\)

b) 

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23 tháng 12 2016

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

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

\(=\left(x^2-1\right)^2+6x\left(x^2-1\right)+9x^2\)

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

b, \(x^4-7x^3+14x^2-7x+1\)

\(=x^4+2x^2+1+7x^3+12x^2-7x\)

\(=\left(x^2+1\right)^2-7x\left(x^2+1\right)+12^2\)

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

c, \(12x^2-11x-36\)

\(=12x^2-27x+16x-36\)

\(=3x\left(4x-9\right)+4\left(4x-9\right)\)

\(=\left(4x-9\right)\left(3x+4\right)\)

1) \(x^2+6x+8\)

\(=x^2+2x+4x+8\)

\(=x\left(x+2\right)+4\left(x+2\right)\)

\(=\left(x+4\right)\left(x+2\right)\)

2) \(x^2-5x-14\)

\(=x^2-7x+2x-14\)

\(=x\left(x-7\right)+2\left(x-7\right)\)

\(=\left(x-7\right)\left(x+2\right)\)

3) \(2x^2+5x+3\)

\(=2x^2+2x+3x+3\)

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

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

4) \(x^2-x-12\)

\(=x^2-4x+3x-12\)

\(=x\left(x-4\right)+3\left(x-4\right)\)

\(=\left(x-4\right)\left(x+3\right)\)

18 tháng 8 2017

x+ 7x - 6=x2 . x + 7x - 22 + 2 = (x2 - 22) + (x+7x)+2=(x-2) . (x+2) + 8x + 2

x3 - 5x + 8x - 4=x2 . x -5x + 8x -22 = (x2 - 22) . (x -5x + 8x )=(x-2) . (x+2) . 4x

x3 - 9x2 + 6x + 16=x2 . x - 9x2 + 6x + 16 = (x- 9x2) . (x+6x) + 16=(x-9x) . (x+9x) . 7x + 16

k mk nha

10 tháng 10 2018

a) \(x^2-6x+8\)

\(=x^2-2\cdot x\cdot3+3^2-1\)

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

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

\(=\left(x-4\right)\left(x-2\right)\)

Còn lại tương tự

a) \(x^2-6x+8=x^2-2x-4x+8\)                     

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

=x(x-2)-4(x-2) = (x-2)(x-4)

13 tháng 11 2016

a) nhận xét hệ số : 1 + 4 - 29 + 24 = 0

=> x3 + 4x2 - 29x + 24 = x2(x-1) + 5x(x-1) - 24(x-1)

= (x-1)(x2+5x-24) = (x-1)(x-3)(x+8)

b) ...

13 tháng 11 2016

a) \(x^3+4x^2-29x+24\)=\(\left(x+8\right)\left(x^2-4x+3\right)\)=\(\left(x+8\right)\left(x^2-x-3x+3\right)\)=\(\left(x+8\right)\left(x-1\right)\left(x-3\right)\)

b) \(x^4+6x^3+7x^2-6x+1\)=\(x^4+3x^3-x^2+3x^3+9x^2-3x-x^2-3x+1\)=\(x^2\left(x^2+3x-1\right)+3x\left(x^2+3x-1\right)-\left(x^2+3x-1\right)\)=\(\left(x^2+3x-1\right)\left(x^2+3x-1\right)\)=\(\left(x^2+3x-1\right)^2\)

16 tháng 7 2018

a)   \(x^3-2x^2-6x+12\)

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

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

\(=\left(x-2\right)\left(x-\sqrt{6}\right)\left(x+\sqrt{6}\right)\)

b)  \(x^4-7x^2+12\)

\(=x^4-3x^2-4x^2+12\)

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

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

\(=\left(x-\sqrt{3}\right)\left(x+\sqrt{3}\right)\left(x-2\right)\left(x+2\right)\)

c)  \(x^2-5x+4\)

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

\(=x\left(x-1\right)-4\left(x-1\right)\)

\(=\left(x-1\right)\left(x-4\right)\)

d)  \(3x^2+5x+2\)

\(=3x^2+3x+2x+2\)

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

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

e)  \(x^3-x+3x^2y+3xy^2+y^3-y\)

\(=\left(x+y\right)^3-\left(x+y\right)\)

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

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

5 tháng 11 2018

a) \(x^{12}-3x^6+1\)

\(=\left(x^6\right)^2-2\cdot x^6\cdot1+1^2-x^6\)

\(=\left(x^6-1\right)^2-\left(x^3\right)^2\)

\(=\left(x^6-x^3-1\right)\left(x^6+x^3-1\right)\)

5 tháng 11 2018

b) \(x^4+6x^3+7x^2-6x+1\)

\(=x^4+\left(6x^3-2x^2\right)+\left(9x^2-6x+1\right)\)

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

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