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18 tháng 8 2022

đk x khác 0 ; 1 

\(\dfrac{x^3-x^2-8}{x^3-x^2}=2\Rightarrow1-\dfrac{8}{x^2\left(x-1\right)}=2\Leftrightarrow\dfrac{8}{x^2\left(x-1\right)}=-1\)

\(\Leftrightarrow x^2\left(1-x\right)=8\Leftrightarrow-x^3+x^2-8=0\Leftrightarrow x=1,71...\)(tm) 

8 tháng 7 2019

3. ( 22 + 1 ).( 24 + 1 ).( 28 + 1 )......( 264 + 1 ) + 1

= ( 22 - 1 ).( 22 + 1 ).( 24 + 1 ).( 28 + 1 )....( 264 + 1 ) + 1

= ( 24 - 1 ).( 24 + 1 ).( 28 + 1 )......( 264 + 1 ) + 1

= ( 28 + 1 ).....( 264 + 1 )  + 1

= ( 264 - 1 ).( 264 + 1 ) + 1

=  2128 - 1 + 1

= 2128

8 tháng 7 2019

8.( 32 + 1 ).( 34 + 1 ).( 38 + 1 )....( 3128 + 1 ) + 1

= ( 32 - 1 ).( 32 + 1 ).( 34 + 1 ).( 38 + 1 )....( 3128 + 1 ) + 1

= ( 34 - 1 ).( 34 + 1 ).( 38 + 1 )....( 3128 + 1 ) + 1

= ( 38 - 1 ).( 38 + 1 )....( 3128 + 1 ) + 1

= ( 316 - 1 )......( 3128 + 1 ) + 1

= ( 3128 - 1 ).( 3128 + 1 ) + 1

=  3256 - 1 + 1

= 3256

10 tháng 12 2022

1: \(=\dfrac{x^2\cdot4xy^2}{x^2}=4xy^2\)

2: \(=\dfrac{3x\left(x-2\right)}{-\left(x-2\right)}=-3x\)

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

6: \(\dfrac{5\left(x-y\right)^4-3\left(x-y\right)^3+4\left(x-y\right)^2}{\left(x-y\right)^2}=5\left(x-y\right)^2-3\left(x-y\right)+4\)

 

21 tháng 10 2019

Phân tích đa thức thành nhân tử bằng cách phối hợp nhiều phương pháp

1 tháng 1 2018

a) \(\dfrac{x^2+2}{x^3-1}+\dfrac{2}{x^2+x+1}+\dfrac{1}{1-x}\)

\(=\dfrac{x^2+2}{\left(x-1\right)\left(x^2+x+1\right)}+\dfrac{2}{x^2+x+1}-\dfrac{1}{x-1}\)

\(=\dfrac{x^2+2+2\left(x-1\right)-\left(x^2+x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}\)

\(=\dfrac{x^2+2+2x-2-x^2-x-1}{\left(x-1\right)\left(x^2+x+1\right)}\)

\(=\dfrac{x-1}{\left(x-1\right)\left(x^2+x+1\right)}\)

\(=\dfrac{1}{x^2+x+1}\)

b) \(\dfrac{9}{x^3-9x}-\dfrac{-1}{x+3}\)

\(=\dfrac{9}{x\left(x-3\right)\left(x+3\right)}+\dfrac{1}{x+3}\)

\(=\dfrac{9+x\left(x-3\right)}{x\left(x-3\right)\left(x+3\right)}\)

\(=\dfrac{9+x^2-3x}{x\left(x-3\right)\left(x+3\right)}\)

c) \(\dfrac{x^3-8}{5x+10}.\dfrac{x^2+4x}{x^2+2x+4}\)

\(=\dfrac{x\left(x-2\right)\left(x^2+2x+4\right)\left(x+4\right)}{5\left(x+2\right)\left(x^2+2x+4\right)}\)

\(=\dfrac{x\left(x-2\right)\left(x+4\right)}{5\left(x+2\right)}\)

d) \(\dfrac{5x+10}{4x-8}.\dfrac{4-2x}{x+2}\)

\(=\dfrac{5\left(x+2\right)}{4\left(x-2\right)}.\dfrac{2\left(2-x\right)}{x+2}\)

\(=-\dfrac{10\left(x+2\right)\left(x-2\right)}{4\left(x-2\right)\left(x+2\right)}\)

\(=-\dfrac{5}{2}\)

e) \(\dfrac{\left(x-13\right)^2}{2x^5}.\dfrac{-3x^2}{x-13}\)

\(=\dfrac{x-13}{2x^3}.\dfrac{-3}{1}\)

\(=\dfrac{-3\left(x-13\right)}{2x^3}\)

g) \(\dfrac{x^2+6x+9}{1-x}.\dfrac{\left(x-1\right)^2}{2\left(x+3\right)^2}\)

\(=-\dfrac{\left(x+3\right)^2}{x-1}.\dfrac{\left(x-1\right)^2}{2\left(x+3\right)^2}\)

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

\(=-\dfrac{x-1}{2}\).

7 tháng 8 2017

1,x(2x-7)-4x-14=x(2x-7)-2(2x-7)=(2x-7)(x-2)