K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

13 tháng 2 2022

x + 3/x - 3 - x - 3/x + 3 = 36/x^2 - 9

<=>(x + 3)^2 - (x - 3)^2/(x - 3)(x + 3) = 36/x^2 - 9

<=>x^2 + 6x + 9 - x^2 + 6x - 9/x^2 - 9 = 36/x^2 - 9

<=>12x = 36 <=> x = 3

13 tháng 2 2022

đk : x khác 3 ; -3 

\(\dfrac{\left(x+3\right)^2-\left(x-3\right)^2}{x^2-9}=\dfrac{36}{x^2-9}\Rightarrow x^2+6x+9-x^2+6x-9=36\)

\(\Leftrightarrow12x=36\Leftrightarrow x=3\)(ktmđk)

vậy pt vô nghiệm 

8 tháng 10 2021

\(d,\Leftrightarrow x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=15\\ \Leftrightarrow24x=-10\Leftrightarrow x=-\dfrac{5}{12}\\ e,\Leftrightarrow x^3-3x^2+3x-1+8-x^3+3x^2+6x=17\\ \Leftrightarrow9x=10\Leftrightarrow x=\dfrac{10}{9}\\ f,\Leftrightarrow9x^2+18x+9-18x=36+x^3-27\\ \Leftrightarrow x^3-9x^2=0\Leftrightarrow x^2\left(x-9\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=9\end{matrix}\right.\)

30 tháng 7 2019

\(\left(y-2\right)\left(y-3\right)+\left(y-2\right)-1=0\)

\(\Leftrightarrow\left(y-2\right)\left(y-3\right)+\left(y-3\right)=0\)

\(\Leftrightarrow\left(y-3\right)^2=0\)

\(\Leftrightarrow y=3\)

\(x^3+27+\left(x+3\right)\left(x-9\right)=0\)

\(\Leftrightarrow\left(x+3\right)\left(x^2-3x+9\right)+\left(x+3\right)\left(x-9\right)=0\)

\(\Leftrightarrow\left(x+3\right)\left(x^2-3x+9+x-9\right)=0\)

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

\(\Leftrightarrow\left(x+3\right)x\left(x-2\right)=0\)

\(\Leftrightarrow x\in\left\{0;-3;2\right\}\)

30 tháng 7 2019

Bài làm

Vì ( y - 2 ) . ( y - 3 ) + ( y - 2 ) - 1 = 0

=> ( y - 2 ) = 0 hoặc ( y - 3 ) + ( y - 2 ) - 1 = 0

=> y = 2 hoặc y = 3 

Vậy y = 2 hoặc y = 3

~ Mấy câu còn lại làm tương tự. Làm theo mẫu câu a . b = 0 , => a = 0 hoặc b = 0. ~
# Chúc bạn học tốt # 

23 tháng 7 2021

b)(x+3)2-(x-4)(x+8)=1

\(\Rightarrow\)x2+6x+9-(x2+8x-4x-32)=1

⇒x2+6x+9-x2-8x+4x+32=1

⇒2x+41=1

\(\Rightarrow\)2x+41-1=0

\(\Rightarrow\)2x+40=0

⇒2x=-40

\(\Rightarrow\)x=\(\dfrac{-40}{2}\)

⇒x=-20

a) Ta có: \(\dfrac{x}{x-3}-\dfrac{6}{x}-\dfrac{9}{x^2-3x}\)

\(=\dfrac{x^2}{x\left(x-3\right)}-\dfrac{6\left(x-3\right)}{x\left(x-3\right)}-\dfrac{9}{x\left(x-3\right)}\)

\(=\dfrac{x^2-6x+18-9}{x\left(x-3\right)}\)

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

b) Ta có: \(\dfrac{7}{x}-\dfrac{x}{x+6}+\dfrac{36}{x^2+6x}\)

\(=\dfrac{7\left(x+6\right)-x^2+36}{x\left(x+6\right)}\)

\(=\dfrac{7x+42-x^2+36}{x\left(x+6\right)}\)

\(=\dfrac{-\left(x^2-7x-78\right)}{x\left(x+6\right)}\)

\(=\dfrac{-\left(x^2-13x+6x-78\right)}{x\left(x+6\right)}\)

\(=\dfrac{-\left[x\left(x-13\right)+6\left(x-13\right)\right]}{x\left(x+6\right)}\)

\(=\dfrac{13-x}{x}\)

c) Ta có: \(\dfrac{6}{x-3}-\dfrac{2x-6}{x^2-9}-\dfrac{4}{x+3}\)

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

\(=\dfrac{6x+18-2x+6-4x+12}{\left(x-3\right)\left(x+3\right)}=\dfrac{36}{\left(x-3\right)\left(x+3\right)}\)

1 tháng 3 2023

a)

\(\dfrac{x-2}{4}+\dfrac{2x-3}{3}=\dfrac{x-18}{6}\)

`<=> 3x-6+8x-12=2x-36`

`<=> 3x+8x-2x=-36+6+12`

`<=> 9x=-18`

`<=> x=-2`

b)

\(\dfrac{x+3}{x-3}+\dfrac{3-x}{x+3}=\dfrac{36}{x^2-9}\left(x\ne3;x\ne-3\right)\)

suy ra

`(x+3)^2 +(3-x)(x-3)=36`

`<=>x^2 +6x+9+3x-9-x^2 +3x=36`

`<=> x^2 -x^2 +6x+3x+3x+9-9-36=0`

`<=> 12x-36=0`

`<=> 12x=36`

`<=> x=3 (KTMĐK)

24 tháng 12 2021

b: \(=\dfrac{7x-42-x^2+36}{x\left(x-6\right)}=\dfrac{-x^2+7x-6}{x\left(x-6\right)}=\dfrac{-x+1}{x}\)

24 tháng 12 2021

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