Giúp mình vứoi mm ơi mình vote cho 5 sao

Đáp án:

1. `x^2 + 2019x – 2020`

`= x^2 – x + 2020x – 2020`

`= x(x – 1) + 2020(x – 1)`

`= (x – 1)(x + 2020)`

2.`2020x^2 – x – 2021`

` = 2020x^2 – 2021x + 2020x – 2021`

`=x(2020x – 2021) + (2020x – 2021)`

`= (x + 1)(2020x – 2021)`

3. `3x^2 – 7x – 10`

`= 3x^2 + 3x – 10x – 10`

`= 3x(x + 1) – 10(x + 1)`

`= (x + 1)(3x – 10)`

4. `5x^2 + 17x – 22`

`= 5x^2 – 5x + 22x – 22`

`= 5x(x – 1) + 22(x – 1)`

`= (x – 1)(5x + 22)`

5. `100x^2 + 100x – 201` (Đề sai)

6. `x^3 – 15x^2 + 56x`

`= x^3 – 8x^2 – 7x^2 + 56x`

`= x^2 .(x – 8) – 7x(x – 8)`

`= x(x – 8)(x – 7)`

7.`x^3 + x^2 – 20x`

`= x^3 – 4x^2 + 5x^2 – 20x`

`= x^2 .(x – 4) + 5x.(x – 4)`

`= x(x – 4)(x + 5)`

8. `x^3 + 4x^2 – 21x`

`= x^3 – 3x^2 + 7x^2 – 21x`

`= x^2 .(x – 3) + 7x.(x – 3)`

`= x(x – 3)(x + 7)`

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