Question

Phân tích thành nhân tử :

A= 6x - 9 - \(x^2\)

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

Answer 1

\(-A=x^2-6x+9=\left(x-3\right)^2\Rightarrow A=-\left(x-3\right)^2=\left(3-x\right)\left(x-3\right)\) 

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

Answer 2

\(A=6x-9-x^2\) 

  \(=-\left(x^2-6x+9\right)\) 

 \(=-\left(x-3\right)^2\) 

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

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

   \(=\left(4x+2\right).2x\)

Answer 3

\(A=6x-9-x^2\)

\(=-\left(x^2-6x+9\right)\)

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

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

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

\(=\left(4x+2\right).2x\)