Giải phương trình :
\(\frac{60}{x}\)+ \(\frac{6}{x+10}\)=\(\frac{120}{x}\)- \(\frac{1}{x}\)
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\(ĐKXĐ:\hept{\begin{cases}x\ne0\\x\ne30\\x\ne24\end{cases}}\)
Ta có \(\frac{60}{\frac{120}{x}-4}+\frac{60}{\frac{120}{x}-5}=x\)
\(\Leftrightarrow\frac{60}{\frac{120-4x}{x}}+\frac{60}{\frac{120-5x}{x}}=x\)
\(\Leftrightarrow\frac{60x}{120-4x}+\frac{60x}{120-5x}=x\)
\(\Leftrightarrow\frac{60}{120-4x}+\frac{60}{120-5x}=1\left(Do\text{ }x\ne0\right)\)
\(\Leftrightarrow\frac{15}{30-x}=1-\frac{12}{24-x}\)
\(\Leftrightarrow\frac{15}{30-x}=\frac{24-x-12}{24-x}\)
\(\Leftrightarrow\frac{15}{30-x}=\frac{12-x}{24-x}\)
\(\Leftrightarrow360-15x=\left(12-x\right)\left(30-x\right)\)
\(\Leftrightarrow360-15x=360-42x+x^2\)
\(\Leftrightarrow x^2-27x=0\)
\(\Leftrightarrow x\left(x-27\right)=0\)
\(\Leftrightarrow x=27\left(Tm\text{ }ĐKXĐ\right)\)
=>\(\frac{30x\left(x-6\right)}{x\left(x+10\right)\left(x-6\right)}+\frac{30x\left(x+10\right)}{x\left(x+10\right)\left(x-6\right)}=\frac{60\left(x+10\right)\left(x-6\right)}{x\left(x-6\left(x+10\right)\right)}\)
=>30x2-180x+30x2+300x=60x2-360x+600x-3600
=>60x2+120x=60x2+240x-3600
=>-120x=-3600
=>x=30
nhớ k mk........Đúng 100%
a, \(\frac{x+9}{10}+\frac{x+10}{9}=\frac{9}{x+10}+\frac{10}{x+9}\)(1)
ĐKXĐ: \(\hept{\begin{cases}x+9\ne0\\x+10\ne0\end{cases}\Leftrightarrow\hept{\begin{cases}x\ne-9\\x\ne-10\end{cases}}}\)
(1)\(\Leftrightarrow\frac{9.\left(x+9\right)}{90}+\frac{10.\left(x+10\right)}{90}=\frac{9.\left(x+9\right)}{\left(x+9\right)\left(x+10\right)}+\frac{10.\left(x+10\right)}{\left(x+9\right)\left(x+10\right)}\)
\(\Leftrightarrow9.\left(x+9\right)+10.\left(x+10\right)=9.\left(x+9\right)+10.\left(x+10\right)\)
\(\Leftrightarrow9x+81+10x+100=9x+81+10x+100\)
\(\Leftrightarrow9x+10x-9x-10x=81+100-81-100\)
\(\Leftrightarrow0x=0\)
\(\Rightarrow x\in R\)trừ -9 và -10
\(a,\Leftrightarrow5\left(x-2\right)-15x\le9+10\left(x+1\right)\)
\(\Leftrightarrow5x-10-15x\le9+10x+10\)
\(\Leftrightarrow-20x\le29\)
\(\Leftrightarrow x\ge-1,45\)
Vậy ...........
\(b,\Rightarrow\left(x+2\right)-3\left(x-3\right)=5\left(x-2\right)\)
\(\Leftrightarrow x+2-3x+9-5x+10=0\)
\(\Leftrightarrow-7x+21=0\)
\(\Leftrightarrow x=3\)
Vậy ..............
\(\frac{x-2}{6}-\frac{x}{2}\le\frac{3}{10}+\frac{x+1}{3}\Leftrightarrow\frac{5\left(x-2\right)}{30}-\frac{15x}{30}\le\frac{9}{30}+\frac{10\left(x+1\right)}{30}\)
\(\Leftrightarrow5x-10-15x-9-10x-10\le0\)
\(\Leftrightarrow-20x-29\le0\Leftrightarrow\left(-20x\right)\cdot\frac{-1}{20}\ge29\cdot-\frac{1}{20}\)
\(\Leftrightarrow x\ge-\frac{29}{20}\)
a,12x-180+10x-20+39x-2340+65x-4420=780
126x-6960=780
126x=7740
x=430/7
\(\hept{\begin{cases}\frac{x+4}{x+3}-\frac{2}{y-1}=10\\\frac{x+6}{x+3}+\frac{1}{y-1}=7\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}\frac{x+4}{x+3}-\frac{2}{y-1}=10\\\frac{2x+12}{x+3}+\frac{2}{y-1}=14\end{cases}}\)
\(\Leftrightarrow\left(\frac{x+4}{x+3}-\frac{2}{y-1}\right)+\left(\frac{2x+12}{x+3}+\frac{2}{y-1}\right)=24\)
\(\Leftrightarrow\frac{x+4}{x+3}+\frac{2x+12}{x+3}=24\)
\(\Leftrightarrow\frac{x+4+2x+12}{x+3}=24\)
\(\Leftrightarrow\frac{3x+16}{x+3}=24\)
\(\Leftrightarrow3x+16=24x+62\)
\(\Leftrightarrow21x+46=0\)
\(\Rightarrow x=\frac{-46}{21}\)
Okey,giờ tìm y đơn giản rồi nhen :D
Ta có: \(\frac{7}{10}-\frac{5}{8}.x-\frac{7}{6}=\frac{5}{6}.x\)
\(\Rightarrow\frac{7}{10}-\frac{7}{6}=\frac{5}{6}x+\frac{5}{8}x\)
\(\Rightarrow\frac{21}{30}-\frac{35}{30}=\left(\frac{5}{6}+\frac{5}{8}\right)x\)
\(\Rightarrow-\frac{7}{15}=\left(\frac{15}{24}+\frac{20}{24}\right)x\)
\(\Rightarrow-\frac{7}{15}=\frac{35}{24}x\)
\(\Rightarrow x=-\frac{7}{15}:\frac{35}{24}\)
\(\Rightarrow x=-\frac{7}{15}.\frac{24}{35}\)
\(\Rightarrow x=-\frac{8}{25}\)
Vậy \(x=-\frac{8}{25}\)
Chuk bạn hok tốt!
`Answer:`
\(\frac{60}{x}+\frac{6}{x+10}=\frac{120}{x}-\frac{1}{x}\) ĐKXĐ: \(x\ne0;x\ne-10\)
\(\Leftrightarrow\frac{60\left(x+10\right)}{x\left(x+10\right)}+\frac{6x}{x\left(x+10\right)}=\frac{120\left(x+10\right)}{x\left(x+10\right)}-\frac{1\left(x+10\right)}{x\left(x+10\right)}\)
\(\Leftrightarrow60\left(x+10\right)+6x=120\left(x+10\right)-1\left(x+10\right)\)
\(\Leftrightarrow60x+600+6x=120x+1200-x-10\)
\(\Leftrightarrow60x+6x-120x+x=1200-10-600\)
\(\Leftrightarrow-53x=590\)
\(\Leftrightarrow x=-\frac{590}{53}\)