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a) đề kiểu gì vậy bạn
b) \(x+\frac{2}{14}=\frac{3}{21}\Leftrightarrow x=0\)
c) \(x+\frac{2}{7}=\frac{1}{2}\Leftrightarrow x=\frac{3}{14}\)
d) \(\frac{12}{15}=\frac{x-5}{10}\Leftrightarrow15x-75=120\Leftrightarrow15x=195\Leftrightarrow x=13\)
\(a,x.\frac{-3}{7}=\frac{4}{21}\)
\(x=\frac{4}{21}:\frac{-3}{7}\)
\(x=\frac{-4}{9}\)
\(b,\frac{-4}{7}:x=\frac{2}{5}\)
\(x=\frac{-4}{7}:\frac{2}{5}\)
\(x=\frac{-10}{7}\)
\(c,x+\frac{1}{12}=\frac{-3}{8}\)
\(x=\frac{-3}{8}-\frac{1}{12}\)
\(x=\frac{-11}{24}\)
\(d,\frac{2}{15}-x=\frac{-3}{10}\)
\(x=\frac{2}{15}+\frac{3}{10}\)
\(x=\frac{13}{30}\)
\(e,-x+\frac{4}{5}=\frac{1}{2}\)
\(-x=\frac{-3}{10}\)
\(x=\frac{3}{10}\)
\(f,\frac{3}{4}.\left(x+1\right)-\frac{1}{2}=\frac{3}{7}\)
\(\frac{3}{4}.\left(x+1\right)=\frac{13}{14}\)
\(x+1=\frac{26}{21}\)
\(x=\frac{5}{21}\)
\(\frac{-3}{2}-2x+\frac{3}{4}=-2\)
\(\frac{-3}{2}-2x=\frac{-11}{4}\)
\(2x=\frac{-3}{2}+\frac{11}{4}\)
\(2x=\frac{-17}{4}\)
\(x=\frac{-17}{8}\)
\(h,-x+\frac{4}{5}=\frac{1}{2}\)
\(-x=\frac{-3}{10}\)
\(x=\frac{3}{10}\)
chúc bạn học tốt !!!
\(\frac{-2}{7}\div\frac{15}{14}=\frac{-21}{20}\div\left(5\times x\right)\)
\(\Rightarrow\frac{-4}{15}=\frac{-21}{20}\div\left(5\times x\right)\)
\(\Rightarrow5\times x=\frac{-21}{20}\div\frac{-4}{15}\)
\(\Rightarrow5\times x=\frac{63}{16}\)
\(\Rightarrow x=\frac{63}{16}\div5\)
\(\Rightarrow x=\frac{63}{80}\)
~ học tốt nha ~
\(\frac{-2}{7}:\frac{15}{14}=\frac{-21}{20}:(5\cdot x)\)
\(\Leftrightarrow\frac{-21}{20}:(5\cdot x)=\frac{-2}{7}:\frac{15}{14}\)
\(\Leftrightarrow\frac{-21}{20}:(5\cdot x)=\frac{-2}{7}\cdot\frac{14}{15}\)
\(\Leftrightarrow\frac{-21}{20}:(5\cdot x)=\frac{-2}{1}\cdot\frac{2}{15}\)
\(\Leftrightarrow\frac{-21}{20}:(5\cdot x)=\frac{4}{15}\)
\(\Leftrightarrow5\cdot x=\frac{-21}{20}:\frac{4}{15}\)
\(\Leftrightarrow5\cdot x=\frac{-21}{20}\cdot\frac{15}{4}\)
\(\Leftrightarrow5\cdot x=\frac{-21}{4}\cdot\frac{3}{4}\)
\(\Leftrightarrow5\cdot x=\frac{-63}{16}\)
\(\Leftrightarrow x=\frac{-63}{16}:5\)
\(\Leftrightarrow x=\frac{-63}{16}\cdot\frac{1}{5}=\frac{-63}{80}\)
1. áp dụng tính chất của dãy tỉ số bằng nhau ta có :
\(\frac{x+2}{3}=\frac{y-7}{5}=\frac{x+y-5}{3+5}=\frac{16}{8}=2\Rightarrow\hept{\begin{cases}x+2=6\\y-7=10\end{cases}\Leftrightarrow\hept{\begin{cases}x=4\\y=17\end{cases}}}\)
2. áp dụng tính chất của dãy tỉ số bằng nhau ta có :
\(\frac{x+5}{2}=\frac{y-2}{3}=\frac{x+5-y+2}{2-3}=\frac{-10+7}{-1}=3\Rightarrow\hept{\begin{cases}x+5=6\\y-2=9\end{cases}}\Leftrightarrow\hept{\begin{cases}x=1\\y=11\end{cases}}\)
a) x = 201 - 37 - 54 = 110
b) x = (821 + 51) / 47 = 872 / 47
(x-2)/5=(y+5)/7=(x-2+y+5)/12=(x+y-2+5)/12
=(21-2+5)/12=2
=>(x-2)/5=2=>x=12
=>(y+5)/7=2=>y=9
a) \(\text{}/3x-5/-\frac{1}{7}=\frac{1}{3}\) b)\(\left(\frac{3}{5}x-\frac{2}{3}x-x\right).\frac{1}{7}=\frac{-5}{21}\)
\(/3x-5/=\frac{10}{21}\) \([x.\left(\frac{3}{5}-\frac{2}{3}-1\right)]=\frac{-5}{21}.7\)
\(\Rightarrow3x-5=\frac{10}{21}hay3x-5=\frac{-10}{21}\) \(\left[x.\frac{-16}{15}\right]=\frac{-5}{3}\)
\(3x=\frac{115}{21}\) \(3x=\frac{95}{21}\) \(x=\frac{25}{16}\)
\(x=\frac{115}{63}\) \(x=\frac{95}{63}\) Vậy x = \(\frac{25}{16}\)
Vậy x \(\in\left\{\frac{115}{63};\frac{95}{63}\right\}\)