Question

Phân Tích các Đa thức sau thành nhân tử 

x^3+2x^2+xy^2-4x

x^2-6x-7

Answer 1

sửa đề câu a đi 

\(x^2-6x-7=x^2+x-7\left(x+1\right)=\left(x-7\right)\left(x+1\right)\)

Answer 2

+)\(x^3+2x^2+xy^2-4x\)

\(=x^3+xy^2+2x^2-4x\)

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

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

+) \(x^2-6x-7\)

\(=x^2-6x+9-16\)

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

\(=\left(x-3-4\right)\left(x-3+4\right)=\left(x-7\right)\left(x+1\right)\)

Answer 3

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

\(x^2-6x-7=x\left(x+1\right)-7\left(x+1\right)=\left(x-7\right)\left(x+1\right)\)

Answer 4

Bài làm 

a, \(x^3+2x^2+xy^2-4x=x\left(x^2+2x+y^2-4\right)\)

b, \(x^2-6x-7=x\left(x+1\right)-7\left(x+1\right)=\left(x-7\right)\left(x+1\right)\)

Answer 5

x³ + 2x² + xy² - 4x 

= ( x³ + xy² ) + ( 2x² - 4x )

= x( x² + y² ) + x( 2x - 4 )

= x( x² + y² + 2x - 4 )

x² - 6x - 7

= x² + x - 7x - 7

= x( x + 1 ) - 7( x + 1 )

= ( x - 7 )( x + 1 )