A. (X – 9)2 – (X + 3)2A. 4X(X – 3) – 3X(2 +X)B. (X + 1)2 + (X - 3)2 –...

1. Thu gọn:

a. (x – 9)

²

– (x + 3)

²

a. 4x(x – 3) – 3x(2 +x)

b. (x + 1)

²

+ (x - 3)

²

– 2(x + 1)(x - 3)

b.

^{2x 5x 2}

(

^{+ +}

) (

^{2x 3 3x 1}

⁻

) (

⁻

)

c. (x – 2)

²

– (x – 2)(x + 3)

c. (x – 1)

²

– (x + 2)(x - 2)