Question

Phân tích đa thức sau thành nhân tử bằng phương pháp nhóm nhiều hạng tử :

a) ( x - 3)( x - 1) - 3(x-3)

b) x³ - 2x² + 2x - 13

c) x²y + xy + x + 1

d) x² - ( a+b)x + ab 

e) x² - 2x -4y² - 4y

Answer 1

a) \(\left(x-3\right)\left(x-1\right)-3\left(x-3\right)\)

\(=\left(x-3\right)\left(x-1-3\right)\)

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

Answer 2

c) x^2y+xy+x+1=xy(x+1)+x+1=(x+1)(xy+1)    d)x^2-ax-bx+ab=x(x-a)-b(x-a)=(x-a)(x-b)        d)  (x^2-4y^2)-(2x+4y)=(x+2y)(x-2y)-2(x+2y)=(x+2y)(x-2y-2)

Answer 3

a)\((x-3)(x-1)-3(x-3)\)

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

b)\(x^3-2x^2+2x-13\)

Sai đề

c)\(x^2y+xy+x+1\)

\(=\left(x+1\right)\left(xy+1\right)\)

d)\(x^2-(a+b)x+ab\)

\(=\left(x-a\right)\left(x-b\right)\)

e)\(x^2-2x-4y^2-4y\)

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

Answer 4

a)\((x-3)(x-1)-3(x-3)\)

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

b)\(x^3-2x^2+2x-13\)

Sai đề

c)\(x^2y+xy+x+1\)

\(=\left(x+1\right)\left(xy+1\right)\)

d)\(x^2-(a+b)x+ab\)

\(=\left(x-a\right)\left(x-b\right)\)

e)\(x^2-2x-4y^2-4y\)

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