Question

:Phân tích đa thức thành nhân tử bằng phương pháp đặt nhân tử chung 

a)9x^2y^2 + 15x^2y – 25xyz  

b)2x( x-3)^2 – 3(x-3)

c)3x(x+5) –y(x+5) +(x+5)^2

Answer 1

a: \(=xy\left(9xy+15x-25z\right)\)

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

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

\(=\left(x+5\right)\left(4x+5-y\right)\)

Answer 2

\(a,9x^2y^2+15x^2y-25xyz=xy\left(9xy+15x-25z\right)\)
\(b,2x\left(x-3\right)^2-3\left(x-3\right)=2x\left(x-3\right)\left(x-3\right)-3\left(x-3\right)=\left(x-3\right)\left[2x\left(x-3\right)-3\right]=\left(x-3\right)\left[2x^2-6x-3\right]\)
\(c,3x\left(x+5\right)-y\left(x+5\right)+\left(x+5\right)^2=3x\left(x+5\right)-y\left(x+5\right)+\left(x+5\right)\left(x+5\right)=\left(x+5\right)\left(3x+y+x+5\right)=\left(x+5\right)\left(4x+y+5\right)\)

Answer 3

A. Tịt 

B. \(x=1\dfrac{1}{2}-\sqrt{\dfrac{15}{2}}\) 

    \(x=\) \(3\)

    \(x=\sqrt{\dfrac{15}{2}}\) \(+\dfrac{1}{2}\)

 

C. ( - ( x + 5))(y - 4x - 5)