Question

Bài 2: Phân tích đa thức thành nhân tử.

a) 14x²y – 21xy² + 28x²y                                             b) x(x + y) – 5x – 5y.

c) 10x(x – y) – 8(y – x).                                              d) (3x + 1)² – (x + 1)²

 

Answer 1

\(14x^2y-21xy^2+28x^2y=7xy\left(2x-3y+4x\right)=21xy\left(2x-y\right)\)

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

\(10x\left(x-y\right)-8\left(y-x\right)=10x\left(x-y\right)+8\left(x-y\right)=2\left(x-y\right)\left(5x+4\right)\)

\(\left(3x+1\right)^2-\left(x+1\right)^2=\left(3x+1-x-1\right)\left(3x+1+x+1\right)=2x\left(4x+2\right)=4x\left(2x+1\right)\)