a) ( x 2  – 4x + 1)( x 2  – 2x + 3).

b) ( x 2  + 5x – 1)( x 2  + x – 1).

Bài 1 :

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

Bài 2 :

 \(x^8+x^7+1=x^8+x^7+x^6+x^5+x^4+x^3+x^2+x+1-x^6-x^5-x^4-x^3-x^2-x\)

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

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

Tick đúng nha 

X^2-6+8

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

Check lại đề hộ mình nhé:vv

3x3 – 6x2 + 3x = 3x(x2 - 2x + 1) = 3x(x - 1)2

7x2+15x-5=0

7*(x2+2.5x-5/7)=0

x2+2*x*1.25+1,5625-255/112=0

(x+1.25)2-255/112=0

\(\text{ 2x² + 6x - 8 }\)

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

Ta có x 2 – 6x + 8

= x 2 – 4x – 2x + 8

= x(x – 4) – 2(x – 4)

= (x – 4)(x – 2)

Đáp án cần chọn là: A

\(2x^4-7x^3+17x^2-20x+14\)

\(=2x^4-3x^3+7x^2-4x^3+6x^2-14x+4x^2-6x+14\)

\(=x^2\left(2x^2-3x+7\right)-2x\left(2x^2-3x+7\right)+2\left(2x^2-3x+7\right)\)

\(=\left(x^2-2x+2\right)\left(2x^2-3x+7\right)\)

6x³+5x²+6x-8 

= 6x³-4x²+9x²-6x+12x-8

=2x².(3x-2)+3x.(3x-2)+4.(3x-2)

=(3x-2)(2x²+3x+4)

a) x² + 6x + 9 = x² + 2 . x . 3 + 3² = (x + 3)²

b) 10x – 25 – x² = -(-10x + 25 +x²) = -(25 – 10x + x²)

                         = -(5² – 2 . 5 . x – x²) = -(5 – x)²

c) 8x³ - 1/8 = (2x)³ – (1/2)³ = (2x - 1/2)[(2x)² + 2x . 12 + (1/2)²]

                    ^{= (2x - 1/2)(4x2 + x + 1/4)} 

d)1/25x² – 64y² = (1/5x)2(1/5x)2- (8y)² = (1/5x + 8y)(1/5x - 8y)