Phân tích đa thức -> nhân tử. 1. `1-4x^2` 2. `(x+5)(4x-1)+x^2-25` 28/09/2021 Bởi Everleigh Phân tích đa thức -> nhân tử. 1. `1-4x^2` 2. `(x+5)(4x-1)+x^2-25`
Câu 1: 1 – 4x² ⇔ 1² – (2x)² ⇔ (1 – 2x).(1+2x) Câu 2: (x +5).(4x – 1) + x² – 25 ⇔ (x +5).(4x – 1) + ( x – 5).(x + 5) ⇔ ( x + 5). ( 4x – 1 + x – 5) ⇔ ( x + 5). ( 5x – 6) Bình luận
`a)` `1-4x^2` `=(1-2x)(1+2x)` `b)` `(x+5)(4x-1)+x^2-25` `=(x+5)(4x-1)+(x+5)(x-5)` `=(x+5)(4x-1+x-5)` `=(x+5)(5x-6)` Bình luận
Câu 1: 1 – 4x² ⇔ 1² – (2x)² ⇔ (1 – 2x).(1+2x)
Câu 2: (x +5).(4x – 1) + x² – 25
⇔ (x +5).(4x – 1) + ( x – 5).(x + 5)
⇔ ( x + 5). ( 4x – 1 + x – 5)
⇔ ( x + 5). ( 5x – 6)
`a)` `1-4x^2`
`=(1-2x)(1+2x)`
`b)` `(x+5)(4x-1)+x^2-25`
`=(x+5)(4x-1)+(x+5)(x-5)`
`=(x+5)(4x-1+x-5)`
`=(x+5)(5x-6)`