A) X2 + 4Y2 + 4XY – 16 = (X + 2Y)2 -16 = (X + 2Y – 4)(X + 2Y + 4)...

Bài 1a) x

²

+ 4y

²

+ 4xy – 16 = (x + 2y)

²

-16 = (x + 2y – 4)(x + 2y + 4).b) 5x

²

- 10xy + 5y

²

= 5(x

²

- 2xy + y

²

) = 5(x - y)

²