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23 tháng 10 2019

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

Đặt \(x^2+5x+6=t\)Thay vào (1) ta được:

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

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

\(=t^2-4x^2\)

\(=\left(t-2x\right)\left(t+2x\right)\)Thay \(t=x^2+5x+6\)ta được:

\(\left(x^2+5x+6-2x\right)\left(x^2+5x+6+2x\right)\)

\(=\left(x^2+3x+6\right)\left(x^2+7x+6\right)\)

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

\(=\left(x^2+3x+6\right)\left[x\left(x+1\right)+6\left(x+1\right)\right]\)

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

22 tháng 12 2023

Bài 2:

1: \(\left(2x-1\right)^2-4\left(2x-1\right)=0\)

=>\(\left(2x-1\right)\left(2x-1-4\right)=0\)

=>(2x-1)(2x-5)=0

=>\(\left[{}\begin{matrix}2x-1=0\\2x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=\dfrac{5}{2}\end{matrix}\right.\)

2: \(9x^3-x=0\)

=>\(x\left(9x^2-1\right)=0\)

=>x(3x-1)(3x+1)=0

=>\(\left[{}\begin{matrix}x=0\\3x-1=0\\3x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{1}{3}\\x=-\dfrac{1}{3}\end{matrix}\right.\)

3: \(\left(3-2x\right)^2-2\left(2x-3\right)=0\)

=>\(\left(2x-3\right)^2-2\left(2x-3\right)=0\)

=>(2x-3)(2x-3-2)=0

=>(2x-3)(2x-5)=0

=>\(\left[{}\begin{matrix}2x-3=0\\2x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{5}{2}\end{matrix}\right.\)

4: \(\left(2x-5\right)\left(x+5\right)-10x+25=0\)

=>\(2x^2+10x-5x-25-10x+25=0\)

=>\(2x^2-5x=0\)

=>\(x\left(2x-5\right)=0\)

=>\(\left[{}\begin{matrix}x=0\\2x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{5}{2}\end{matrix}\right.\)

Bài 1:

1: \(3x^3y^2-6xy\)

\(=3xy\cdot x^2y-3xy\cdot2\)

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

2: \(\left(x-2y\right)\left(x+3y\right)-2\left(x-2y\right)\)

\(=\left(x-2y\right)\cdot\left(x+3y\right)-2\cdot\left(x-2y\right)\)

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

3: \(\left(3x-1\right)\left(x-2y\right)-5x\left(2y-x\right)\)

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

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

\(=\left(x-2y\right)\left(8x-1\right)\)

4: \(x^2-y^2-6y-9\)

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

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

\(=\left(x-y-3\right)\left(x+y+3\right)\)

5: \(\left(3x-y\right)^2-4y^2\)

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

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

\(=\left(3x-3y\right)\left(3x+y\right)\)

\(=3\left(x-y\right)\left(3x+y\right)\)

6: \(4x^2-9y^2-4x+1\)

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

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

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

8: \(x^2y-xy^2-2x+2y\)

\(=xy\left(x-y\right)-2\left(x-y\right)\)

\(=\left(x-y\right)\left(xy-2\right)\)

9: \(x^2-y^2-2x+2y\)

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

\(=\left(x-y\right)\left(x+y\right)-2\left(x-y\right)\)

\(=\left(x-y\right)\left(x+y-2\right)\)

15 tháng 9 2021

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

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

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

\(D=x^3-16x=x\left(x^2-16\right)=x\left(x-4\right)\left(x+4\right)\)

\(E=4x^2-25y^2=\left(2x-5y\right)\left(2x+5y\right)\)

\(G=\left(2x+3\right)^2-\left(2x-3\right)^2=\left(2x+3-2x+3\right)\left(2x+3+3x-3\right)=6.4x=24x\)

15 tháng 9 2021

\(A=2x\left(2x+3\right)\\ B=\left(2x+3\right)\left(2x+3-x\right)=\left(2x+3\right)\left(x+3\right)\\ C=\left(3x-1\right)\left(3x+1\right)-\left(3x-1\right)^2\\ =\left(3x-1\right)\left(3x+1-3x+1\right)\\ =2\left(3x-1\right)\\ D=x\left(x^2-16\right)=x\left(x-4\right)\left(x+4\right)\\ E=\left(2x-5y\right)\left(2x+5y\right)\\ G=\left(2x+3-2x+3\right)\left(2x+3+2x-3\right)\\ =24x\)

11 tháng 10 2020

Rút gọn thôi chứ phân tích sao được ._.

( x - 3 )2 - ( 4x + 5 )2 - 9( x + 1 )2 - 6( x - 3 )( x + 1 )

= x2 - 6x + 9 - ( 16x2 + 40x + 25 ) - 9( x2 + 2x + 1 ) - 6( x2 - 2x - 3 )

= x2 - 6x + 9 - 16x2 - 40x - 25 - 9x2 - 18x - 9 - 6x2 + 12x + 18

= -30x2 - 52x - 7

11 tháng 10 2020

Sửa đề lại 1 chút là phân tích được mà bn Quỳnh:))

Ta có: \(\left(x-3\right)^2-\left(4x+5\right)^2+9\left(x+1\right)^2-6\left(x-3\right)\left(x+1\right)\)

\(=\left[\left(x-3\right)^2-6\left(x-3\right)\left(x+1\right)+9\left(x+1\right)^2\right]-\left(4x+5\right)^2\)

\(=\left(x-3-9x-9\right)^2-\left(4x+5\right)^2\)

\(=\left(8x+12\right)^2-\left(4x+5\right)^2\)

\(=\left(4x+7\right)\left(12x+17\right)\)

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

Đặt \(x^2+3x+1=a,\)ta được:

\(a\left(a+1\right)-6\)

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

\(=a\left(a+3\right)-2\left(a+3\right)=\left(a+3\right)\left(a-2\right)\)

Thay \(a=x^2+3x+1,\)ta được:

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

`#3107.101107`

`(4x - 1)^2 - 121`

`= (4x - 1)^2 - (11)^2`

`= (4x - 1 - 11)(4x - 1 + 11)`

`= (4x - 12)(4x + 10)`

`= 4(x - 3) * 2(2x + 5)`

`= 8(x - 3)(2x + 5)`

_____

`x^6 - y^6`

`= (x^3)^2 - (y^3)^2`

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

`= (x - y)(x^2 + xy + y^2)(x + y)(x^2 - xy + y^2)`

`= (x - y)(x + y)(x^2 + xy + y^2)`

____

Sử dụng các HĐT:

`@` `A^2 - B^2 = (A - B)(A + B)`

`@` `A^3 - B^3 = (A - B)(A^2 + AB + B^2)`

`@` `A^3 + B^3 = (A + B)(A^2 - AB + B^2).`

11 tháng 12 2023

a: \(\left(4x-1\right)^2-121\)

\(=\left(4x-1\right)^2-11^2\)

\(=\left(4x-1-11\right)\left(4x-1+11\right)\)

\(=\left(4x-12\right)\left(4x+10\right)\)

\(=8\left(x-3\right)\left(2x+5\right)\)

b: \(x^6-y^6\)

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

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

6 tháng 1 2018

Ta có (6x+5)2(3x+2)(x+1)-35

= (36x2+60x+25)(3x2+5x+2)-35 (1)

Đặt a=3x2+5x+2

=> 12a+1= 12(3x2+5x+2)+1 =36x2+60x+25

Thay a=3x2+5x+2 vào (1) ta được

(12a+1).a-35=12a2+a-35

= 12a2-20a+21a-35

= 4a(3a-5)+7(3a-5)

= (3a-5)(4a+7) (2)

Thay 3x2+5x+2=a vào (2) ta được

(9x2+15x+6-5)(12x2+20x+8+7)

= (9x2+15x+1)(12x2+20x+15)

Ta có: \(\left(6x+5\right)^2\left(3x+2\right)\left(x+1\right)-35\)

\(=\left(36x^2+60x+25\right)\left(3x^2+5x+2\right)-35\)(1)

Đặt \(3x^2+5x+2=y\)

\(\left(1\right)=\left(12y+1\right)y-35\)

\(=12y^2+y-35\)

\(=\left(3y-5\right)\left(4y+7\right)\)

\(=\left(9x^2+15x+1\right)\left(12x^2+20x+15\right)\)