Question

Câu 2. (2 điểm): Phân tích đa thức thành nhân tử.

a) $5 x^2-10 x$;

b) $x^2-y^2-2 x+2 y$;

c) $x^2+10 x-y^2+25$.

Answer 1

\(5x^2-10x=5x.\left(x-2\right)\\ x^2-y^2-2x+2y=\left(x^2-y^2\right)-\left(2x-2y\right)\\ =\left(x-y\right).\left(x+y\right)-2.\left(x-y\right)\\ =\left(x+y-2\right).\left(x-y\right)\\ x^2+10x-y^2+25=\left(x^2+10x+25\right)-y^2\\ =\left(x+5\right)^2-y^2=\left(x+5-y\right).\left(x+5+y\right)\)

Answer 2

a 5x²-10x

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

b x²-y²-2x+2y

= x.x -y.y-2x+2y

=2xy²

cx²+10x - y²+25

=x.x + 5x.2-y.y+5.5

=5xy(2x)

Answer 3

Answer 4

5x(x-2)

(x-y)(x+y-2)

(x+5-y)(x+5+y)

Answer 5

Answer 6

a) 5x(x-2)

B) (2X+2Y)(X2-Y2)

C) 5XY(X+2-Y+5)

Answer 7

a) 5x² - 10x

= 5x(x - 2)

b)x² - y² - 2x + 2y

= (x - y)(x + y) - 2(x-y)

= (x - y)(x + y -2)

c) x² + 10x - y² + 25

= (x² + 10x + 25) - y²

= (x + 5)² - y²

= (x + 5 -y)(x + 5 +y) 

Answer 8

5x 

2

 −10x=5x.(x−2)

x 

2

 −y 

2

 −2x+2y=(x 

2

 −y 

2

 )−(2x−2y)

=(x−y).(x+y)−2.(x−y)

=(x+y−2).(x−y)

x 

2

 +10x−y 

2

 +25=(x 

2

 +10x+25)−y 

2

 

=(x+5) 

2

 −y 

2

 =(x+5−y).(x+5+y)

Answer 9

76gre

 

Answer 10

Answer 11

5x^2 -10x = 5x (1 - 20)

b x^2 -Y^2 - 2x +2y 

= ( x -y )^2 - 2(x +y)

c x^2 +10x -y^2 +25

( x - y)^ 2  + 10x +25