\(a,=x\left(x-3\right)\\ b,=\left(x-y\right)^2-4=\left(x-y-2\right)\left(x-y+2\right)\\ c,=\left(3x+7\right)\left(x-2\right)+2\left(x-2\right)=\left(x-2\right)\left(3x+9\right)=3\left(x+3\right)\left(x-2\right)\)

\(1,=x\left(x^2-2x+1-y^2\right)=x\left[\left(x-1\right)^2-y^2\right]=x\left(x-y-1\right)\left(x+y-1\right)\\ 2,=\left(x+y\right)^3\\ 3,=\left(2y-z\right)\left(4x+7y\right)\\ 4,=\left(x+2\right)^2\\ 5,Sửa:x\left(x-2\right)-x+2=0\\ \Leftrightarrow\left(x-2\right)\left(x-1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)

56.B

57.B

58.B

56B

57B

58B

Hình như ở câu phân tích đa thức đề là (3x+5)(x-2) chứ không phải (x+2)

1..

(x+1)(2-x)-(3x+5)(x+2)

=(x+1)(2-x)+(3x-5)(2-x)

=(2-x)(x+1+3x-5)

=(2-x)(4x-4)

2...

(3x-5)(2x+7)-(x+1)(6x-5)=16

=>(6x²⁺21x-10x-35)-(6x²-5x+6x-5)-16=0

=>6x²⁺21x-10x-35-6x²+5x-6x+5-16=0

=>(6x²-6x²)+(21x-10x+5x-6x)+(-35+5-16)=0

=>10x-46=0

=>10x     =46

=>    x     =4.6

 Vậy x=4.6(bạn nên đổi ra phân số thì sẽ đúng hơn)

\(x^4-4x^3-2x^2-3x+2\)

\(\Leftrightarrow x^4+x^3-5x^3+x^2-5x^2+2x^2-5x+2x+2\)

\(\Leftrightarrow x^4+x^3+x^2-5x^3-5x^2-5x+2x^2+2x+2\)

\(\Leftrightarrow x^2\left(x^2+x+1\right)-5x\left(x^2+x+1\right)+2\left(x^2+x+1\right)\)

\(\Leftrightarrow\left(x^2-5x+2\right)\left(x^2+x+1\right)\)

Xin tick ạ !!!

Ta có

2x^4-x^3+2x^2+3x-2

=x^3(2x-1)+(2x^2-x)+(4x-2)

=x^3(2x-1)+x(2x-1)+2(2x-1)

=(x^3+x+2)(2x-1)

Bạn ơi , tìm x 

a) xy+3x-7y-21

=x(y+3)-7(x+3)

=(x-7)(y+3)

b)2xy-15-6x-5y

=2x(y-3)-5(-3+y)

=(2x-5)(y-3)

c)2x^2y+2xy^2-2x-2y

=2x(xy-1)+2y(xy-1)

=(2x+2y)(xy-1)

x(x+3)-5x(x-5)-5(x+3)

=(x-5)(x+3)-5x(x-5)

=(x-5)(x+3-5x)

Câu cuối mình bị nhầm dòng cuối phải là (x-5)(x+3+x-5)=(x-5)(2x-2)nha bạn

a) xy+3x-7y-21=(xy+3x)-(7y+21)= x(y+3)-7(y+3)=(y+3)(x-7)

b)2xy-15-6x+5y=(2xy-6x)+(5y-15)=2x(y-3)+5(y-3)=(y-3)(2x+5)

c)2x^2y+2xy^2-2x-2y=2xy(x+y)-2(x+y)=2(x+y)(xy-1)

d) x(x+3)-5x(x-5)-5(x+3)=[x(x+3)-5(x+3)]-5x(x-5)=(x+3)(x-5)-5x(x-5)=(x-5)(x+3-5x)=(x-5)(3-4x)

\(3x\left(x+1\right)^2-5x^2\left(x+1\right)+7\left(x+1\right)\)

\(=\left(x+1\right)\left(3x^2+3x-5x^2+7\right)\)

\(=\left(x+1\right)\left(-2x^2+3x+7\right)\)

\(x^4+3x^2-2x+3\)

\(=x^4+x^3-x^3+3x^2+x^2-x^2-3x+x+3\)

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

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

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

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