Đáp án+Giải thích các bước giải:
a, (x + 2y)² = x² + 4xy + 4y²
b, (3x - 2y)² = 9x² - 12xy + 4y²
c, (2x - $\dfrac{1}{2}$ )³ = 8x³ - 6x² + $\dfrac{3}{2}$x - $\dfrac{1}{8}$
d, ($\dfrac{x}{2}$ - y).($\dfrac{x}{2}$ + y) = ($\dfrac{x}{2}$)² - y²
= $\dfrac{x²}{4}$ - y²
e, (x + $\dfrac{1}{3}$)³ = x³ + x² + $\dfrac{1}{3}$x + $\dfrac{1}{27}$
f, (x - 2).(x² + 2x + 4) = x³ - 8
