Phân tích các đa thức sau thành nhân tử : a) x³ – x² b) 6x² – 2x c) 5xy – 10x d) 2x² – 8x + 4 j) 3/7x² + 5x³ + x²y² g) 5xy² + 10xy – 15x²y² Làm đúng

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1. $\text{a) x³ – x².}$

   $\text{= x².x – x².1.}$

   $\text{= x².(x – 1).}$

   $\text{b) 6x² – 2x.}$

   $\text{= 2x.3x – 2x.1.}$

   $\text{= 2x.(3x – 1).}$

   $\text{c) 5xy – 10x.}$

   $\text{= 5x.y – 5x.2.}$

   $\text{= 5x.(y – 2).}$

   $\text{d) 2x² – 8x + 4.}$

   $\text{= 2.x² – 2.4x + 2.2.}$

   $\text{= 2.(x² – 4x + 2).}$

   $\text{j) $\dfrac{3}{7}$x² + 5x³ + x²y².}$

   $\text{= $\dfrac{3}{7}$.x² + 5x.x² + x².y².}$

   $\text{= x².($\dfrac{3}{7}$ + 5x + y²).}$

   $\text{g) 5xy² + 10xy – 15x²y².}$

   $\text{= 5xy.y + 5xy.2 – 5xy.3xy.}$

   $\text{= 5xy.(y + 2 – 3xy.}$

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