Question

Phân tích các đa thức sau thành nhân tử

a) 2x³+ 6x= 2x.( x² +3)

b) 5x. (x-2) - 3x².( x-2)

c) 3x.(x-5y)- 2y. (5y-x)

d) y². (x²+ y)- zx²- xy

e) 2ax³+ 4bx²y + 2x². (ã-by)

f) 3x². (y²- 2x)- 15x. (2x-y)²

Answer 1

a) \(2x^3+6x=2x\left(x^2+3\right)\)

\(\Leftrightarrow2x^3+6x=2x^3+6x\)

\(\Leftrightarrow0x=0\)

b) \(5x\left(x-2\right)-3x^2\left(x-2\right)=x\left(x-2\right)\left(5-3x\right)\)

c) \(3x\left(x-5y\right)-2y\left(5y-x\right)=\left(x-5y\right)\left(3x+2y\right)\)

e) \(2ax^3+4bx^2y+2x^2\left(ax-by\right)=2x^2\left(ax+2by\right)+2x^2\left(ax-2by\right)\)

\(=2x^2\left(ax+2by+ax-2by\right)=4ax^3\)

f) \(3x^2\left(y^2-2x\right)-15x\left(2x-y\right)^2=-3x\left(2x-y^2\right)\left(x+5\right)\)