Question

Phân tích đa thức sau thành nhân tử
 

c) x² – y² + 3x – 3y

d) x³ + 3x² – 16x – 48              

Answer 1

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

d: \(=x^2\left(x+3\right)-16\left(x+3\right)\)

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

Answer 2

x² – y² + 3x – 3y

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

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

x³ + 3x² – 16x – 48       

`=x^2(x+3) -  16(x+3)`

`=(x^2-16)(x+3)`

Answer 3

c)

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

d)

\(x^3+3x^2-16x-48\\ =x\left(x^2-16\right)+3\left(x^2-16\right)\\ =\left(x^2-16\right)\left(x+3\right)\\ =\left(x+4\right)\left(x-4\right)\left(x+3\right)\)