Ai làm giúp tôi với

1. (x+2y)2 = x² +2.x.2y + (2y)²

= x² + 4xy + 4y²

2. (2x + 3y)² = 4x² + 12xy + 9y²

3. (3y - 2y)² = 9x² - 12xy + 4y²

4. (5x - y)² = 25x² - 10xy + y²

5. (x + 1/4)² = x² + 1/2x + 1/16

6. (2x - 1/2)² = 4x² - 2x + 1/4

7. (1/3x - 1/2y)² = 1/9x² - 1/3xy + 1/4 y²

8. (3x + 1) (3x-1) = 9x² - 1

9. (x² + 2/5y) (x² - 2/5y)

= (x²)² - (2/5y)²

= x⁴ - 4/25y

10. (x/2 - y) (x/2 + y) = x²/4 - y²

11. (x/2 - 2y)² =x²/4−2xy + 4y²

12. $(\sqrt{2x}-y^{)}$² = 2x - 2y $\sqrt{2x}+y^2$

13. (3/2x + 3y)² =9x²/4 + 9xy + 9y²