\(\frac{3}{5x+5}+\frac{x-6}{10x-10}\)
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\(a,\frac{3}{2x+6}-\frac{x-6}{2x^2+6x}\) (x khác -3; khác 0)
\(=\frac{3}{2\left(x+3\right)}-\frac{x-6}{2x.\left(x+3\right)}=\frac{3x}{2x.\left(x+3\right)}-\frac{x-6}{2x.\left(x+3\right)}=\frac{3x-x+6}{2x.\left(x+3\right)}=\frac{2x+6}{x.\left(2x+6\right)}=\frac{1}{x}\)
\(b,\left(\frac{2x+1}{2x-1}-\frac{2x-1}{2x+1}\right):\frac{4x}{10x-5}\) (x khác 0 , khác 1/2 khác -1/2 )
\(=\left(\frac{\left(2x+1\right)^2}{\left(2x-1\right)\left(2x+1\right)}-\frac{\left(2x-1\right)^2}{\left(2x-1\right)\left(2x+1\right)}\right).\frac{10x-5}{4x}\)
\(=\left(\frac{4x^2+4x+1}{\left(2x-1\right)\left(2x+1\right)}-\frac{4x^2-4x+1}{\left(2x-1\right)\left(2x+1\right)}\right).\frac{10x-5}{4x}\)
\(=\frac{8x}{\left(2x-1\right)\left(2x+1\right)}.\frac{5.\left(2x-1\right)}{4x}=\frac{10}{2x+1}\)
\(\frac{x}{5x+5}-\frac{x}{10x-10}\)
\(=\frac{x}{5\left(x+1\right)}-\frac{x}{10\left(x-1\right)}\)
\(=\frac{2x\left(x-1\right)-x\left(x+1\right)}{10\left(x+1\right)\left(x-1\right)}\)
\(=\frac{2x^2-2x-x^2-x}{10\left(x+1\right)\left(x-1\right)}\)
\(=\frac{x^2-3x}{10\left(x+1\right)\left(x-1\right)}\)
\(=\frac{x\left(x+1\right)}{5\left(x^2-2x+1\right)}.\frac{5\left(x-1\right)}{3\left(x+1\right)}=\frac{x\left(x+1\right).5\left(x-1\right)}{5\left(x-1\right)^2.3\left(x+1\right)}=\frac{x}{3x-3}\)
\(\frac{x^2+x}{5x^2-10x+5}:\frac{3x+3}{5x-5}\)
=\(\frac{x\left(x+1\right)}{5\left(x^2-2+1\right)}:\frac{3\left(x+1\right)}{5\left(x-1\right)}\)
=\(\frac{x\left(x+1\right)}{5\left(x-1\right)^2}:\frac{3\left(x+1\right)}{5\left(x-1\right)}\)
=\(\frac{x\left(x+1\right)}{5\left(x-1\right)^2}\cdot\frac{5\left(x-1\right)}{3\left(x+1\right)}\)
=\(\frac{x}{3\left(x-1\right)}\)
bằng
\(\frac{x}{5\left(x+1\right)}\)-\(\frac{x}{10\left(x-1\right)}\)=\(x\left(\frac{1}{5\left(x+1\right)}-\frac{1}{10\left(x-1\right)}\right)\)=\(x\left(\frac{2\left(x-1\right)}{10\left(x+1\right)\left(x-1\right)}-\frac{x+1}{10\left(x-1\right)\left(x+1\right)}\right)\)
=\(x\left(\frac{2\left(x-1\right)-\left(x+1\right)}{10\left(x+1\right)\left(x-1\right)}\right)\)=\(x\left(\frac{2x-2-x+1}{10\left(x-1\right)\left(x+1\right)}\right)\)=\(x\left(\frac{x-1}{10\left(x-1\right)\left(x+1\right)}\right)\)=\(x\left(\frac{1}{10\left(x+1\right)}\right)\)=\(\frac{x}{10x+10}\)
\(\Rightarrow\frac{x}{5\left(x+1\right)}-\frac{x}{10\left(x-1\right)}\)
\(\Leftrightarrow\frac{2x\left(x-1\right)}{10\left(x+1\right)\left(x-1\right)}-\frac{x\left(x+1\right)}{10\left(x-1\right)\left(x+1\right)}\)
\(\Leftrightarrow\frac{2x\left(x-1\right)-x\left(x+1\right)}{10\left(x+1\right)\left(x-1\right)}\)
\(\Leftrightarrow\frac{2x^2-2x-x^2-x}{10\left(x+1\right)\left(x-1\right)}\)\(\Leftrightarrow\frac{x^2-3x}{10\left(x+1\right)\left(x-1\right)}\)
\(\Rightarrow\frac{x}{5x+5}-\frac{x}{10x-10}=\frac{x^2-3x}{10\left(x+1\right)\left(x-1\right)}\)
\(\frac{x^3+2x^2}{2x^2+10x}\)+\(\frac{2x^2-10x+10x-50}{2x^2-10x}\)+\(\frac{50-5x}{2x^2+10x}\)=\(\frac{x^3+4x^2-5x}{2x^2-10x}\)=\(\frac{x\left(x^2+4x-5\right)}{2x\left(x-5\right)}\)=\(\frac{x\left(x-1\right)\left(x-5\right)}{2x\left(x-5\right)}\)=\(\frac{x-1}{2}\)
a) \(\frac{5x-2}{3}=\frac{5-3x}{2}\)\(\Leftrightarrow2\left(5x-2\right)=3\left(5-3x\right)\)\(\Leftrightarrow10x-4=15-9x\)
\(\Leftrightarrow10x+9x=15+4\)\(\Leftrightarrow19x=19\)\(\Rightarrow x=1\)
Vậy tập nghiệm của phương trình là: \(S=\left\{1\right\}\)
b) \(\frac{10x+3}{12}=1+\frac{6+8x}{9}\)\(\Leftrightarrow\frac{3\left(10x+3\right)}{36}=\frac{36}{36}+\frac{4\left(6+8x\right)}{36}\)
\(\Leftrightarrow3\left(10x+3\right)=36+4\left(6+8x\right)\)\(\Leftrightarrow30x+9=36+24+32x\)\(\Leftrightarrow32x-30x=9-36-24\)\(\Leftrightarrow2x=-51\)\(\Leftrightarrow x=\frac{-51}{2}\)
Vậy tập nghiệm của phương trình là \(S=\left\{\frac{-51}{2}\right\}\)
c) \(2\left(x+\frac{3}{5}\right)=5\left(\frac{13}{5}+x\right)\)\(\Leftrightarrow2\left(\frac{5x}{5}+\frac{3}{5}\right)=5\left(\frac{13}{5}+\frac{5x}{5}\right)\)\(\Leftrightarrow\frac{2\left(5x+3\right)}{5}=\frac{5\left(13+5x\right)}{5}\)
\(\Leftrightarrow2\left(5x+3\right)=5\left(13+5x\right)\)\(\Leftrightarrow10x+6=65+25x\)\(\Leftrightarrow25x-10x=6-65\)\(\Leftrightarrow15x=-59\)\(\Leftrightarrow x=\frac{-59}{15}\)
Vậy tập nghiệm của phương trình là \(S=\left\{\frac{-59}{15}\right\}\)
\(a,\frac{5x-2}{3}=\frac{5-3x}{2}\)
\(< =>\frac{\left(5x-2\right)2}{3.2}=\frac{\left(5-3x\right)3}{2.3}\)
\(< =>\frac{10x-4}{6}=\frac{15-9x}{6}\)
\(< =>10x-4=15-9x\)
\(< =>10x+9x=15+4=19\)
\(< =>19x=19< =>x=1\)
a) \(x^3-2x^2-5x+6=0\)
\(x^3-x^2-x^2+x-6x+6=0\)
\(x^2\left(x-1\right)-x\left(x-1\right)-6\left(x-1\right)=0\)
\(\left(x-1\right)\left(x^2-x-6\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-1=0\\x^2-x-6=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=1\\x^2-2x+3x-6=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=1\\\left(x+3\right)\left(x-2\right)=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=1\\x=\left\{2;-3\right\}\end{cases}}\)
\(a,x^3-2x^2-5x+6=0\)
\(\Leftrightarrow\left(x^3-x^2\right)-\left(x^2-x\right)-\left(6x-6\right)=0\)
\(\Leftrightarrow x^2\left(x-1\right)-x\left(x-1\right)-6\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x^2-x-6\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left[\left(x^2-3x\right)+\left(2x-6\right)\right]=0\)
\(\Leftrightarrow\left(x-1\right)\left[x\left(x-3\right)+2\left(x-3\right)\right]=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+2\right)\left(x-3\right)=0\)
\(\Leftrightarrow x-1=0\left(h\right)x+2=0\left(h\right)x-3=0\)
\(\Leftrightarrow x=1\left(h\right)x=-2\left(h\right)x=3\)
Vậy \(x\in\left\{-2;1;3\right\}\)
P/S: (h) là hoặc nhé
Đề sai