Phân tích đa thức thành nhân tử 3x ² +14x - 15 Ko bt có phải đề sai ko ạ?

`3x^2` `+` `14x` `-` `15`

`=` `3(x^2 + 14/3x - 5)`

`=` `3(x^2 + 14/3x + 49/9 - 94/9)`

`=` `3(x^2 + 14/3x + 49/9)` `-` `94/3`

`=` `3(x + 7/3)^2` `-` `(sqrt{94/3})^2`

`=` `[sqrt{3} . (x + 7/3)]^2` `-` `(sqrt{94/3})^2`

`=` `(sqrt{3}x + (7sqrt{3})/3)^2` `-` `(sqrt{94/3})^2`

`=` `(sqrt{3}x + (7sqrt{3})/3 -sqrt{94/3})(sqrt{3}x + (7sqrt{3})/3 + sqrt{94/3})`

`=` `(sqrt{3} + (7sqrt{3} - sqrt{94})/3)(sqrt{3}x + (7sqrt{3} + sqrt{94})/3)`