\(x^3-27x-54\)

\(=x^3-6x^2+6x^2-36x+9x-54\)

\(=x^2\left(x-6\right)+6x\left(x-6\right)+9\left(x-6\right)\)

\(=\left(x-6\right)\left(x^2+6x+9\right)=\left(x-6\right)\left(x+3\right)^2\)

       \(4x^3-13x^2+9x-18\)

\(=4x^3-12x^2-x^2+3x+6x-18\)

\(=4x^2\left(x-3\right)-x\left(x-3\right)+6\left(x-3\right)\)

\(=\left(x-3\right)\left(4x^2-x+6\right)\)

\(27x^3-27x^2+18x-4=27x^3-9x^2-18x^2+6x+12x-4\)

\(=9x^2\left(3x-1\right)-6x\left(3x-1\right)+4\left(3x-1\right)\)

\(=\left(3x-1\right)\left(9x^2-6x+4\right)\)

      \(27x^3-27x^2+18x-4=27x^3-9x^2-18x^2+6x+12x-4\)

\(=9x^2\left(3x-1\right)-6x\left(3x-1\right)+4\left(3x-1\right)\)

\(=\left(3x-1\right)\left(9x^2-6x+4\right)\)

bằng phương thức nào bạn ?

câu trả lời:

3x.x-13.x+6²

bằng phương pháp đặt nhân tử chung

THAM KHẢO NHÉ BẠN, MÌNH KO VT ĐC TRONG NÀY NÊN PHẢI RA WORD VÍT R COPY VÀO Á:

$7x^2-13x+6=0\iff 7x^2-7x-6x+6=0$

$\iff 7x\left(x-1\right)-6\left(x-1\right)=0\iff \left(7x-6\right)\left(x-1\right)=0$

x=1;x=67

`#040911`

`7x^2 - 13x + 6`

`= 7x^2 - 7x - 6x + 6`

`= (7x^2 - 7x) - (6x - 6)`

`= 7x(x - 1) - 6(x - 1)`

`= (7x - 6)(x - 1)`

\(7x^2-13x+6=7\left(x-1\right)\left(x-\dfrac{6}{7}\right)\)

\(=6x^2+3x+10x+5=3x\left(2x+1\right)+5\left(2x+1\right)=\left(3x+5\right)\left(2x+1\right)\)

6x2+3x+10x+5=3x(2x+1)+5(2x+1)=(3x+5)(2x+1)

\(-x^3+9x^2-27x+27=\left(3-x\right)^3\)

\(-x^3+9x^2-27x+27\)

\(=-x^3+3x^2+6x^2-18x-9x+27\)

\(=-x^2\left(x-3\right)+6x\left(x-3\right)-9\left(x-3\right)\)

\(=-\left(x-3\right)\left(x^2-6x+9\right)\)

\(=-\left(x-3\right)\left(x-3\right)^2\)

\(=\left(3-x\right)^3\)

=6x^2 - 4x - 9x +6

=(6x^2 -4x) - (9x-6)

=2x(3x -2) - 3(3x-2)

=(3x-2) (2x - 3)