Giúp mình vứoi mm ơi mình vote cho 5 sao Question Giúp mình vứoi mm ơi mình vote cho 5 sao in progress 0 Môn Toán Helga 4 years 2020-11-16T13:17:02+00:00 2020-11-16T13:17:02+00:00 1 Answers 75 views 0
Answers ( )
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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