Đáp án:

Giải thích các bước giải:

 `1) (2x)^2 + 2.2x.3y +(3y)^2`

`= (2x + 3y)^2`

`2) (5x)^2 + 2.5x.(-3y) + (-3y)^2`

`= (5x - 3y)^2`

`3) (4x)^2 - 2.4x.5y + (5y)^2`

`= (4x - 5y)^2`

`4) (7x)^2 - 2.7x.(-4y) + (-4y)^2`

`= (7x - 4y)^2`

`5) (5x)^2 - (4y)^2`

`= (5x - 4y)(5x + 4y)`

`6) (2x)^2 - (8y)^2`

`= (2x - 8y)(2x + 8y)`

`7) (2x)^3 + (4y)^3`

`= (2x + 4y)(4x^2 - 8xy + 16y^2) `

`8) (3x)^3 + (-4y)^3`

`= (3x - 4y)(9x^2 + 12xy + 16y^2)`

`9) (5a)^2 - 2.5a.3b + (3b)^2`

`= (5a - 3b)^2`

`10) (9x)^2 - 2.9x.7y + (7y)^2`

`= (9x - 7y)^2`

`11) (5x)^3 + 3.(5x)^2 . 4y + 3.5x.(4y)^2 + (4y)^3`

`= (5x + 4y)^3`

`12) (2x)^3 + 3.(2x)^2 . 5y + 3.2x.(5y)^2 + (5y)^3`

`= (2x + 5y)^3`

`13) (2x)^3 - 3.(2x)^2 .4y + 3.2x.(4y)^2 + (-4y)^3`

`= (2x - 4y)^3`

`14) (5x)^3 + 3.(5x)^2 .4y + 3.5x.(4y)^2 + (4y)^2`

`= (5x + 4y)^3`

`15) (2x)^3 - (5y)^3`

`= (2x - 5y)(4x^2 + 10xy + 25y^2)`

`16) (-2x)^3 + (4y)^3`

`= (-2x + 4y)(4x^2 - 8xy + 16y^2)`

#Chii

#Team: Extensive Knowledge

1) (2x)² + 2.2x.3y + (3y)² = (2x + 3y)²

2) (5x)² + 2.5x.(-3y) + (-3y)² = [5x + (-3y)]²

3) (4x)² - 2.4x.5y + (5y)² = (4x - 5y)²

4) (7x)² - 2.7x.(-4y) + (-4y)² = [7x - (-4y)]²

5) (5x)² - (4y)² = (5x + 4y) (5x - 4y)

6) (2x)² - (8y)² = (2x + 8y) (2x - 8y)

7) (2x)³ + (4y)³ = (2x + 4y) [(2x)² - 2x . 4y + (4y)²]

                        = (2x + 4y) (4x² - 8xy + 16y²)

8) (3x)³ + (-4y)³ = [3x + (-4y)] [(3x)² - 3x . (-4y) + (-4y)²]

                          = [3x + (-4y)] [9x² - (-12xy) + 16y²]

9) (5a)² - 2.5a.3b + (3b)² = (5a - 3b)²

10) (9x)² - 2.9x.7y + (7y)² = (9x - 7y)²

11) (5x)³ + 3.(5x)².4y + 3.5x.(4y)² + (4y)³ = (5x + 4y)³

12) (2x)³ + 3.(2x)².5y + 3.2x.(5y)² + (5y)³ = (2x + 5y)³

13) (2x)³ - 3.(2x)².4y + 3.2x.(-4y)² + (-4y)³ = (2x - 4y)³

14) (5x)³ + 3.(5x)².4y + 3.5x.(4y)² + (4y)³= (5x + 4y)³

15) (2x)³ - (5y)³ = (2x - 5y) [(2x)² + 2x.5y + (5y)²]

                         = (2x - 5y) (4x² + 10xy + 25y²)

16) (-2x)³ + (4y)³ = (-2x + 4y) [(-2x)²  - (-2x).4y + (4y)²]

                            = (-2x + 4y) [4x² - (-8xy) + 16y²]

Chúc bn học tốt!!!!!

vote 5*, ctlhn