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28 tháng 6 2019
Câu 1 :
\(a,2\left(\frac{3}{4}-5x\right)=\frac{4}{5}-3x\)
\(\Rightarrow\frac{3}{2}-10x=\frac{4}{5}-3x\)
\(\Rightarrow7x=\frac{3}{2}-\frac{4}{5}\)
\(\Rightarrow7x=\frac{7}{10}\)\(\Leftrightarrow x=0,1\)
\(b,\frac{3}{2}-4\left(\frac{1}{4}-x\right)=\frac{2}{3}-7x\)
\(\Rightarrow\frac{3}{2}-1+4x=\frac{2}{3}-7x\)
\(\Rightarrow11x=\frac{2}{3}+1-\frac{3}{2}\)
\(\Rightarrow11x=\frac{4+6-9}{6}-\frac{1}{6}\)
\(\Rightarrow x=\frac{1}{66}\)
28 tháng 6 2019
Câu 2 :
\(a,\frac{2}{x-1}< 0\)
Vì \(2>0\Rightarrow\)để \(\frac{2}{x-1}< 0\)thì \(x-1< 0\Leftrightarrow x< 1\)
\(b,\frac{-5}{x-1}< 0\)
Vì \(-5< 0\)\(\Rightarrow\)để \(\frac{-5}{x-1}< 0\)thì \(x-1>0\Rightarrow x>1\)
\(c,\frac{7}{x-6}>0\)
Vì \(7>0\Rightarrow\)để \(\frac{7}{x-6}>0\)thì \(x-6>0\Rightarrow x>6\)
CW
3 tháng 9 2016
\(\frac{x}{2}-\left(\frac{3x}{5}-\frac{13}{5}\right)=-\left(\frac{7}{5}+\frac{7}{10}x\right)\)
\(\frac{x}{2}-\frac{3x}{5}-\frac{13}{5}=-\frac{7}{5}-\frac{7}{10}x\)
\(\left(\frac{1}{2}-\frac{3}{5}+\frac{7}{10}\right)x=-\frac{7}{5}+\frac{13}{5}\)
\(\frac{3}{5}x=\frac{6}{5}\)
\(x=2\)
28 tháng 3 2020
\(a,x.\frac{-3}{7}=\frac{4}{21}\)
\(x=\frac{4}{21}:\frac{-3}{7}\)
\(x=\frac{-4}{9}\)
\(b,\frac{-4}{7}:x=\frac{2}{5}\)
\(x=\frac{-4}{7}:\frac{2}{5}\)
\(x=\frac{-10}{7}\)
\(c,x+\frac{1}{12}=\frac{-3}{8}\)
\(x=\frac{-3}{8}-\frac{1}{12}\)
\(x=\frac{-11}{24}\)
\(d,\frac{2}{15}-x=\frac{-3}{10}\)
\(x=\frac{2}{15}+\frac{3}{10}\)
\(x=\frac{13}{30}\)
28 tháng 3 2020
\(e,-x+\frac{4}{5}=\frac{1}{2}\)
\(-x=\frac{-3}{10}\)
\(x=\frac{3}{10}\)
\(f,\frac{3}{4}.\left(x+1\right)-\frac{1}{2}=\frac{3}{7}\)
\(\frac{3}{4}.\left(x+1\right)=\frac{13}{14}\)
\(x+1=\frac{26}{21}\)
\(x=\frac{5}{21}\)
\(\frac{-3}{2}-2x+\frac{3}{4}=-2\)
\(\frac{-3}{2}-2x=\frac{-11}{4}\)
\(2x=\frac{-3}{2}+\frac{11}{4}\)
\(2x=\frac{-17}{4}\)
\(x=\frac{-17}{8}\)
\(h,-x+\frac{4}{5}=\frac{1}{2}\)
\(-x=\frac{-3}{10}\)
\(x=\frac{3}{10}\)
chúc bạn học tốt !!!
\(\frac{1}{x-1}-\frac{2}{3}\left(\frac{3}{4}-\frac{6}{5}\right)=\frac{5}{2-2x}\)
=> \(\frac{1}{x-1}-\frac{1}{2}+\frac{4}{5}=\frac{5}{-2}.\frac{1}{x-1}\)
=> \(\frac{1}{x-1}+\frac{3}{10}=\frac{-5}{2}.\frac{1}{x-1}\)
=> \(-\frac{5}{2}.\frac{1}{x-1}-\frac{1}{x-1}=\frac{3}{10}\)
=> \(\frac{1}{x-1}.\left(-\frac{7}{2}\right)=\frac{3}{10}\)
=> \(\frac{1}{x-1}=\frac{-3}{35}\)
=> -3(x - 1) = 35
=> -3x + 3 = 35
=> -3x = 32
=> x = -32/3
\(\frac{1}{x-1}-\frac{2}{3}\left(\frac{3}{4}-\frac{6}{5}\right)=\frac{5}{2-2x}\)ĐK \(x\ne1\)
\(\Leftrightarrow\frac{1}{x-1}-\frac{2}{3}\left(-\frac{9}{20}\right)=\frac{5}{2-2x}\)
\(\Leftrightarrow\frac{1}{x-1}+\frac{3}{10}=\frac{5}{2-2x}\)
\(\Leftrightarrow\frac{10\left(2-2x\right)}{10\left(x-1\right)\left(2-2x\right)}+\frac{3\left(x-1\right)\left(2-2x\right)}{10\left(x-1\right)\left(2-2x\right)}=\frac{50\left(x-1\right)}{10\left(2-2x\right)\left(x-1\right)}\)
\(\Leftrightarrow20-20x+12x-6x^2-6=50x-50\)
\(\Leftrightarrow14-8x-6x^2=50x-50\)
\(\Leftrightarrow64-58x-6x^2=0\)
\(\Leftrightarrow-2\left(3x+32\right)\left(x-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=-\frac{32}{3}\left(tm\right)\\x=1\left(ktm\right)\end{cases}}\)