Question

Bài 1. Phân tích đa thức bằng nhân tử.

a) x (x + y) - 3x - 3y
b) x (x + y) - 5x - 5y
c) x (x + y) - 7x - 7y
d) x² (x - y) + 2x - 2y

Answer 1

a) x (x + y) - 3x - 3y

⇔ x ( x + y ) - 3 ( x + y )

⇔  ( x - 3 ) ( x + y )
b) x (x + y) - 5x - 5y

⇔ x ( x + y ) - 5 ( x + y )

⇔  ( x - 5 ) ( x + y )

c) x (x + y) - 7x - 7y

⇔ x ( x + y ) - 7 ( x + y )

⇔  ( x - 7 ) ( x + y )

d) x² (x - y) + 2x - 2y

⇔ x\(^2\) ( x - y ) + 2 ( x - y )

⇔  ( x\(^2\) - 2 ) ( x - y )

 

Answer 2

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

b)\(x\left(x+y\right)-5x-5y=x\left(x+y\right)-5\left(x+y\right)=\left(x+y\right)\left(x-5\right)\)

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

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