K
Khách

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

9 tháng 2 2017

b) đặt x^2+2x+2=t => t>0

\(\frac{t-1}{t}+\frac{t}{t+1}=\frac{7}{6}\Leftrightarrow\frac{2t^2-1}{t^2+t}=\frac{7}{6}\Leftrightarrow12t^2-6=7t^2+7t\)

\(\Leftrightarrow5t^2-7t-6=0\Leftrightarrow5t\left(t-2\right)+3t-6=\left(t-2\right)\left(5t+3\right)\Rightarrow\left[\begin{matrix}t=2\\t=\frac{-3}{5}\left(loai\right)\end{matrix}\right.\)

với t=2

\(x^2+2x+2=2\Rightarrow x^2+2x=0\Rightarrow\left[\begin{matrix}x=0\\x=-2\end{matrix}\right.\)

4 tháng 2 2017

\(2+\frac{2x^2-8x}{2x^2+8x}+\frac{2x^2+7x+23}{2x^2+7x-4}=\frac{2x+5}{2x-1}\)

\(\Leftrightarrow2+\frac{2x\left(x-4\right)}{2x\left(x+4\right)}+\frac{2x^2+7x+23}{\left(2x-1\right)\left(x+4\right)}=\frac{2x+5}{2x-1}\)

\(\Leftrightarrow2+\frac{x-4}{x+4}+\frac{2x^2+7x+23}{\left(2x-1\right)\left(x+4\right)}-\frac{2x+5}{2x-1}=0\)

\(\Leftrightarrow\frac{2\left(x+4\right)\left(2x-1\right)}{\left(x+4\right)\left(2x-1\right)}+\frac{\left(x-4\right)\left(2x-1\right)}{\left(x+4\right)\left(2x-1\right)}+\frac{2x^2+7x+23}{\left(2x-1\right)\left(x+4\right)}-\frac{\left(2x+5\right)\left(x+4\right)}{\left(2x-1\right)\left(x+4\right)}=0\)

\(\Leftrightarrow\frac{2\left(x+4\right)\left(2x-1\right)+\left(x-4\right)\left(2x-1\right)+2x^2+7x+23-\left(2x+5\right)\left(x+4\right)}{\left(x+4\right)\left(2x-1\right)}=0\)

\(\Leftrightarrow2\left(x+4\right)\left(2x-1\right)+\left(x-4\right)\left(2x-1\right)+2x^2+7x+23-\left(2x+5\right)\left(x+4\right)=0\)

\(\Leftrightarrow2\left(2x^2+7x-4\right)+\left(2x^2-9x+4\right)+2x^2+7x+23-\left(2x^2+13x+20\right)=0\)

\(\Leftrightarrow4x^2+14x-8+2x^2-9x+4+2x^2+7x+23-2x^2-13x-20=0\)

\(\Leftrightarrow6x^2+7x-1=0\)

\(\Leftrightarrow6\left(x^2+2.\frac{7}{12}.x+\frac{49}{144}\right)-\frac{193}{144}=0\)

\(\Leftrightarrow\left(x+\frac{7}{12}\right)^2=\frac{\frac{193}{144}}{6}=\frac{193}{864}\)

Bạn tự làm nốt.

4 tháng 2 2017

Tương tự với Cb.

25 tháng 2 2020

giup minh voi cac bạn

20 tháng 2 2019

\(\frac{x+4}{\left(x-2\right)\left(2x-1\right)}+\frac{x+1}{\left(x-3\right)\left(2x-1\right)}=\frac{2x+5}{\left(x-3\right)\left(2x-1\right)}\)

\(\frac{\left(x-3\right)\left(x+4\right)}{\left(x-2\right)\left(2x-1\right)\left(x-3\right)}+\frac{\left(x+1\right)\left(x-2\right)}{\left(x-3\right)\left(2x-1\right)\left(x-2\right)}=\frac{\left(2x+5\right)\left(x-2\right)}{\left(x-2\right)\left(x-3\right)\left(2x-1\right)}\)

\(\Rightarrow x^2+x-12+x^2-x-2=2x^2+x-10\Leftrightarrow x=-4\)

20 tháng 2 2019

\(\frac{x+4}{2x^2-5x+2}+\frac{x+1}{2x^2-7x+3}=\frac{2x+5}{2x^2-7x+3}\)

\(\Rightarrow\frac{x+4}{2x^2-5x+2}=\frac{2x-5}{2x^2-7x+3}-\frac{x+1}{2x^2-7x+3}\)

\(\Rightarrow\frac{x+4}{2x^2-5x+2}=\frac{x+4}{2x^2-7x+3}\)

TH1:\(x+4\ne0\)

\(\Rightarrow2x^2-5x+2=2x^2-7x+3\)

\(\Rightarrow-5x+2=-7x+3\)

\(\Rightarrow2x=1\)

\(\Rightarrow x=\frac{1}{2}\)

TH2:\(x+4=0\)

\(\Rightarrow x=-4\)