\(a,=\left(2x^4-2x^3+2x^2+3x^3-3x^2+3x-2x^2+2x-2\right):\left(x^2-x+1\right)\\ =\left(x^2-x+1\right)\left(2x^2+3x-2\right):\left(x^2-x+1\right)\\ =2x^2+3x-2\\ b,=\left(6x^2+15x-2x-5\right):\left(2x+5\right)\\ =\left(2x+5\right)\left(3x-1\right):\left(2x+5\right)=3x-1\\ c,=\left(2x^4-6x^2+x^3-3x+x^2-3\right):\left(x^2-3\right)\\ =\left(x^2-3\right)\left(2x^2+x+1\right):\left(x^2-3\right)=2x^2+x+1\)

=> (x^3-2x^2+x-1)(x-5) = x^4-7x^3+11x^2-6x+5

5-/2x+6/-/7-y/

bài 1:

   (-2x^5 y)^8:(-2x^5 y)^6

=(-2x^5 y)^8-6

=(-2x^5y)^2

=4x^25 y^2

a: \(=\dfrac{6x^3+13x^2-5x}{2x+5}=\dfrac{6x^3+15x^2-2x^2-5x}{2x+5}=3x^2-x\)

b: \(=\dfrac{x^4-6x^3+12x^2-14x+3}{x^2-4x+1}\)

\(=\dfrac{x^4-4x^3+x^2-2x^3+8x^2-2x+3x^2-12x+3}{x^2-4x+1}\)

\(=x^2-2x+3\)

d: \(=\dfrac{\left(x+y\right)^2}{x+y}=x+y\)

1.

7x(2x-1)=14x²-7x

2

a. x²+2x=x(x+2)

b.x²-xy+3x-3y

=x(x-y)+3(x-y)

=(x+3)(x-y)

Câu 2:

 1. 2x/2x-5 -  5/2x-5

=2x-5/2x-5

=1

2. (6x³-7x²-x+2) : (x-1)=6x²-x-2

a: \(=-4x^2+20x+2x-10=-4x^2+22x-10\)

b: =x^2-9

c: =x^3+27

d: \(=-2x^2-6x+x+3=-2x^2-5x+3\)

e: =8a^3+1

f: =(3-x)(x+1)(x+2)

=(3-x)(x^2+3x+2)

=3x^2+9x+6-x^3-3x^2-2x

=-x^3+7x+6

Em lớp 5 thôi nhưng em nghĩ bài này nhân vế bình thường thôi ạ 

Ví dụ câu a : \(\left(2x^2+x-1\right)\left(-3x^2-7x-5\right)\)

\(=-6x^4-17x^3-14x^2+2x+5\)

Tương tự chị nhé 

Câu b : 

\(\left(2x^2-3xy+y^2\right)\left(x+y\right)\)

\(=\)\(\left(2x^2-3xy+y^2\right).x+\left(2x^2-3xy+y^2\right).y\)

\(=\)\(2x^3-3x^2y+xy^2+2x^2y-3xy^2+y^3\) 

Câu b : 

\(\left(2x^2-3xy+y^2\right)\left(x+y\right)\)

\(=\left(2x^2-3xy+y^2\right).x+\left(2x^2-3xy+y^2\right).y\)

\(=2x^3-3x^2y+xy^2+2x^2y-3xy^2+y^3\)

\(=2x^3+y^3-x^2y-2xy^2\)

Câu c : 

\(-3x\left(x^2+1\right)\left(-2-x\right)\left(3-2x\right)\)

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

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

\(=18x^3+9x^4+18x+9x^2-12x^4-6x^5-12x^2-6x^3\)

\(=12x^3-3x^4-3x^2+18x-6x^5\)