Question

 Phân tích đa thức thành nhân tử :

a) x² - 6x + 8

b) x² -7xy +10y²

Answer 1

a)  \(x^2+6x+8\)

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

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

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

b) \(x^2-7xy+10y^2\)

\(=x^2-2xy-5xy+10y^2\)

\(=x\left(x-2y\right)-5y\left(x-2y\right)\)

\(=\left(x-2y\right)\left(x-5y\right)\)

Answer 2

a) x² - 6x + 8

= x² -2x - 4x +8

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

= ( x-2)(x-4)

Answer 3

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

b/ \(x^2-7xy+10y^2\) \(=x^2-2xy-5xy+10y^2\) \(=x\left(x-2y\right)-5y\left(x-2y\right)\) \(=\left(x-5y\right)\left(x-2y\right)\)

Answer 4

b) x² - 7xy + 10y² 

= x² -2xy -5xy + 10y² 

= x( x-2y) - 5y( x-2y)

=(x-2y).(x-5y)