Question

Phân tích các đa thức sau thành nhân tử :

+)  x^2-y^2-5x+5y

+)  5x^3-5x^2y-10x^2+10xy

+)  2x^2-5x-7

Answer 1

2x^2-5x-7

=2x^2+2x-7x-7

=2x.(x+!) -7.(x+1)

(2x-7).(x+1)

Answer 2

x^2-y^2-5x+5y

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

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

Answer 3

5x^3-5x^2.y-10x^2+10xy

=5x^2.(x-y)-10x.(x-y)

=(5x^2-10x).(x-y)

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

Answer 4

mk cx ko chắc chắn lắm đâu:)))))

Answer 5

x² - y² - 5x + 5y = ( x² - y² ) - ( 5x - 5y ) = ( x - y )( x + y ) - 5( x - y ) = ( x - y )( x + y - 5 )

5x³ - 5x²y - 10x² + 10xy = 5x²( x - y ) - 10x( x - y ) = ( x - y )( 5x² - 10x ) = 5x( x - y )( x - 2 )

2x² - 5x - 7 = 2x² + 2x - 7x - 7 = 2x( x + 1 ) - 7( x + 1 ) = ( x + 1 )( 2x - 7 )