Question

[bùi thị thu hương]

phân tích đa thức thành nhân tử

1)x²-8x-9

2)x²+3x-18

3)x³-5x²+4x

4)x³-11x²+30x

5)x³-7x-6

6)x¹⁶-64

7)x³-5x²+8x-4

8)x²-3x+2

Answer 1

[Shana]

1)x²-8x-9

= x^2 - 9x +x -9

= x(x+1) - 9 (x+1)

= (x-9) (x+1)

2)x²+3x-18

3)x³-5x²+4x

=x^3 - 4x^2 - x^2 + 4x 

= x^2 (x-1) - 4x(x-1)

= (x^2 - 4x) (x-1)

= x(x-4)(x-1)

4)x³-11x²+30x

5)x³-7x-6

6)x¹⁶-64

\(=\left(x^8\right)^2-8^2\)

\(=\left(x^8-8\right)\left(x^8+8\right)\)

7)x³-5x²+8x-4

8)x²-3x+2

= x^2 - 2x - x +2

= x(x-1) -2(x-1)

= (x-2)(x-1)

Answer 2

[Nguyễn Hà Lan Anh]

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

4)    \(x\left(x-6\right)\left(x-5\right)\)         5)\(\left(x-3\right)\left(x+1\right)\left(x+2\right)\)                               6)   ........

7)  \(\left(x-1\right)\left(x-2\right)\left(x-2\right)\)          8)   \(\left(x-2\right)\left(x-1\right)\)