\(x^2-y^2+6x+9\)

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

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

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

x^2-5x+2xy-10y
phân tích đa thức thành nhân tử

a) x³-2x²-x+2

=x(x²-1)+2(-x²+1)

=x(x²-1)-2(x²-1)

=(x²-1)(x-2)

b)

x²+6x-y²+9

=x²+6x+9-y²

=(x+3)²-y²

^{=(x+3-y)(x+3+y)}

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

x² + 6x + 9

= x² + 2.3.x +  3²

=  (x + 3)²

`x^2 +6x+9`

`=x^2 + 2 . x . 3 + 3^2`

`= (x+3)^2`

x² - 4y² + 9 - 6x 

= (x² - 6x + 9) - (2y)²

= (x - 3)² - (2y)² = (x + 2y - 3)(x - 2y - 3)

b) \(49y^2-x^2+6x-9\)

\(=49y^2-\left(x^2-6x+9\right)\)

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

\(=\left(7y-x+3\right)\left(7y+x-3\right)\)

a) \(a^2-9+6x-x^2\)

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

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

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

- 3x² + (x² - 6x + 9) 

= (x - 3)² - 3x² = (x - 3 - \(\sqrt{3}x\))(x - 3 + \(\sqrt{3}x\))