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20 tháng 8 2016

\(x^3+4x^2+x-6\)

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

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

\(=\left(x-1\right).\left(x^2+5x+6\right)\)

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

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

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

\(\Leftrightarrow\left[\begin{array}{nghiempt}x-1=0\\x+2=0\\x+3=0\end{array}\right.\Leftrightarrow\left[\begin{array}{nghiempt}x=1\\x=-2\\x=-3\end{array}\right.\)

15 tháng 3 2017

thiếu r bạn mà thiếu cái này trầm trọng đếy

15 tháng 10 2021

c: \(x^4+x^3-4x^2+x+1\)

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

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

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

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

14 tháng 11 2021

\(a,=3xy\left(x-2y\right)\\ b,=3\left(x-y\right)+\left(x-y\right)\left(x+y\right)=\left(x+y+3\right)\left(x-y\right)\\ c,=x\left[\left(x+2\right)^2-y^2\right]=x\left(x+y+2\right)\left(x-y+2\right)\\ d,\Leftrightarrow x\left(x^2-4\right)=0\Leftrightarrow x\left(x-2\right)\left(x+2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)

26 tháng 10 2021

a: \(=x^2\left(2x+3\right)+\left(2x+3\right)\)

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

b: \(=\left(x-4\right)\left(x+3\right)\)

e: =(x+3)(x-2)

26 tháng 10 2021

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

b) \(=x\left(x-4\right)+3\left(x-4\right)=\left(x-4\right)\left(x+3\right)\)

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

d) \(=4xy\left(y-3x+2\right)\)

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

f) \(=x\left(x^2+2xy+y^2-4z^2\right)=x\left[\left(x+y\right)^2-4z^2\right]=x\left(x+y-2z\right)\left(x+y+2z\right)\)

g) \(=x\left(x^2-2xy+y^2-25\right)=x\left[\left(x-y\right)^2-25\right]=x\left(x-y-5\right)\left(x-y+5\right)\)

h) \(=x\left(x+1\right)-3\left(x+1\right)=\left(x+1\right)\left(x-3\right)\)

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

a: \(=x\left(x^2+4x+4-z^2\right)\)

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

9 tháng 11 2021

z còn câu b

1b.=2((x+y)+(x+y)(x-y)+(x-y))=2(x2-y2+x+y+x-y)=2(x2-y2+2x)=2x2-2y2+4x

2a.=4xy+4xy+2y=8xy+2y=2y(4x+1)

b.=(3x)2+2.3x.y+y2-(2z)2=(3x+y)2-(2z)2=(3x+y-2z)(3x+y+2z)

c.=x2-x-7x+7=x(x-1)-7(x-1)=(x-1)(x-7)

30 tháng 9 2018

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

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

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

\(=4x^2\)

hk tốt

^^

3 tháng 10 2021

\(a,=x\left(x-2\right)+\left(x-2\right)=\left(x+1\right)\left(x-2\right)\\ b,=4\left(2x^2+x+1\right)\\ c,=x^2\left(2x^2+x+4\right)\)

Đề sai rồi bạn

18 tháng 10 2021

b: \(8x^2-48x+6xy-36y\)

\(=8x\left(x-6\right)+6y\left(x-6\right)\)

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

d: \(a^2-2ab+b^2-4\)

\(=\left(a-b\right)^2-4\)

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

a) Ta có: \(\dfrac{4x^2-3x-7}{A}=\dfrac{4x-7}{2x+3}\)

\(\Leftrightarrow A=\dfrac{\left(2x+3\right)\left(4x^2-3x-7\right)}{4x-7}\)

\(\Leftrightarrow A=\dfrac{\left(2x+3\right)\left(4x-7\right)\left(x+1\right)}{4x-7}\)

\(\Leftrightarrow A=\left(2x+3\right)\left(x+1\right)\)

\(\Leftrightarrow A=2x^2+5x+3\)

b) Ta có: \(\dfrac{1}{B}=\dfrac{a+b}{a^3+b^3}\)

\(\Leftrightarrow\dfrac{1}{B}=\dfrac{a+b}{\left(a+b\right)\left(a^2-ab+b^2\right)}=\dfrac{1}{a^2-ab+b^2}\)

hay \(B=a^2-ab+b^2\)