Phan tich cac da thuc sau thanh phan tu a) 2xy – 10xy² b) x² + 6x + 9

Đáp án:

a) 2xy – 10xy²

= 2xy (1- 5y)

b) x² + 6x + 9

= x² + 3x + 3x + 9

= x (x + 3) + 3(x + 3)

= (x + 3) (x + 3)

= (x + 3)²