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j: \(\Leftrightarrow\left(x-1\right)\left(x-2\right)-x\left(x+2\right)=-5x+2\)
=>x^2-3x+2-x^2-2x=-5x+2
=>-5x+2=-5x+2
=>0x=0(luôn đúng)
k: =>(x-2)^2-3(x+2)=2x-22
=>x^2-4x+4-3x-6=2x-22
=>x^2-7x-2-2x+22=0
=>x^2-9x+20=0
=>x=4 hoặc x=5
a, Ta có: \(\frac{x+2}{x-2}-\frac{1}{x}=\frac{2}{x^2-2x}\)
\(\Leftrightarrow\frac{x+2}{x-2}-\frac{2}{x^2-2x}=\frac{1}{x}\)
\(Đkxđ:\left\{{}\begin{matrix}x\ne2\\x\ne0\end{matrix}\right.\)
\(Pt\Leftrightarrow x\left(x+2\right)-2=x-2\)
\(\Leftrightarrow x^2+x=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\left(ktm\right)\\x=-1\left(tmđk\right)\end{matrix}\right.\)
Vậy .........
\(b,Đkxđ:x\ne-5\)
Ta có: \(\frac{2x-5}{x+5}=3\)
\(\Leftrightarrow2x-5=3\left(x+5\right)\)
\(\Leftrightarrow x=20\left(tmđk\right)\)
Vậy .........
c, \(Đkxđ:x\ne3\)
Ta có: \(\frac{\left(x^2+2x\right)-\left(3x+6\right)}{x-3}=0\)
\(\Leftrightarrow x^2+2x-3x-6=0\)
\(\Leftrightarrow x^2-x-6=0\)
\(\Leftrightarrow x^2-3x+2x-6=0\)
\(\Leftrightarrow x\left(x-3\right)+2\left(x-3\right)=0\)
\(\Leftrightarrow\left(x+2\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+2=0\\x-3=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-2\left(tm\right)\\x=3\left(ktmđk\right)\end{matrix}\right.\)
Vậy ............
\(\frac{x}{x+1}-\frac{2x-3}{x-1}=\frac{2x+3}{x^2-1}\) ĐKXĐ: x ≠ 1; x ≠ -1
⇔x(x - 1) - (2x - 3)(x + 1) = 2x + 3
⇔ x2 - x - 2x2 + 3x - 2x + 3 = 2x + 3
⇔ -x2 - 2x = 0
⇔ -x(x + 2) = 0
⇔ \(\left[{}\begin{matrix}x=0\\x=-2\end{matrix}\right.\) (TM)
Vậy nghiệm của pt là x = 0; x = -2
ĐKXĐ: x≠1; x≠-1
Ta có: \(\frac{x}{x+1}-\frac{2x-3}{x-1}=\frac{2x+3}{x^2-1}\)
\(\Leftrightarrow\frac{x\left(x-1\right)}{\left(x+1\right)\left(x-1\right)}-\frac{\left(2x-3\right)\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}-\frac{2x+3}{\left(x-1\right)\left(x+1\right)}=0\)
\(\Leftrightarrow x^2-x-\left(2x^2+2x-3x-3\right)-\left(2x+3\right)=0\)
\(\Leftrightarrow x^2-x-2x^2+x+3-2x-3=0\)
\(\Leftrightarrow-x^2-2x=0\)
\(\Leftrightarrow-x\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-2\end{matrix}\right.\)
Vậy: x∈{0;-2}
\(\Leftrightarrow\hept{\begin{cases}x\left(x+2\right)-\left(x-2\right)=2\\x\left(x-2\right)\ne0\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}x=0,1\\x\ne0,2\end{cases}}\Rightarrow x=1\)
\(\frac{4x^2-2x}{2x^2+1}\) = 0
Vì 2x2 + 1 \(\ne\) 0 với mọi x
\(\Rightarrow\) 4x2 - 2x = 0
\(\Leftrightarrow\) 2x(2x - 1) = 0
\(\Leftrightarrow\) 2x = 0 hoặc 2x - 1 = 0
\(\Leftrightarrow\) x = 0 hoặc x = \(\frac{1}{2}\)
Vậy S = {0; \(\frac{1}{2}\)}
Chúc bạn học tốt!
\(4x^2-\frac{2x}{2x^2+1}=0\)
\(4x^2\left(2x^2+1\right)-2x=0\)
\(8x^4+4x^2-2x=0\)
\(x\left(4x^3+2x-1\right)=0\)
\(x=0\)