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a,-3/5.2/7+-3/7.3/5+-3/7
=-3/7.2/5+(-3/7).3/5+(-3/7)
=-3/7(2/5+3/5+1)
=-3/7.2
=-6/7
a) \(x+\frac{3}{4}=\frac{-3}{7}\Leftrightarrow x=\frac{-3}{7}-\frac{3}{4}=-\frac{33}{28}\)
b) \(\frac{5}{2}-\left(\frac{3}{2}+x\right)=\frac{7}{4}+\frac{3}{5}=\frac{47}{20}\Rightarrow\frac{3}{2}+x=\frac{5}{2}-\frac{47}{20}=\frac{3}{20}\Rightarrow x=\frac{3}{20}-\frac{3}{2}=-\frac{27}{20}\)
c) \(\frac{3}{7}-\left(\frac{7}{4}-x\right)=\frac{5}{14}\Leftrightarrow\frac{7}{4}-x=\frac{3}{7}-\frac{5}{14}=\frac{1}{14}\Leftrightarrow x=\frac{7}{4}-\frac{1}{14}=\frac{47}{28}\)
d) \(\left[\frac{8}{3}-\left(-x\right)\right]-\left(\frac{-1}{2}\right)=\frac{5}{3}+\frac{1}{6}=\frac{11}{6}\Rightarrow\frac{8}{3}+x+\frac{1}{2}=\frac{11}{6}\)
\(\Rightarrow\frac{8}{3}+x=\frac{11}{6}-\frac{1}{2}=\frac{4}{3}\Rightarrow x=\frac{4}{3}-\frac{8}{3}=-\frac{4}{3}\)
e) \(\frac{3-x}{9}=\frac{4}{3-x}\Leftrightarrow\left(3-x\right)^2=4.9=36\Rightarrow3-x=6\Leftrightarrow x=3-6=-3\)
Câu a:
{3849 - 2.[146 - (2.14 + 6: 2)]} : 32
= {3849 - 2.[146 - (28 + 3)]} : 32
= {3489 - 2.[146 - 31]} : 32
= {3489 - 2.115} : 32
= {3489 - 230} : 32
= 3259 : 32
= 3259/32
Câu b:
134 - 2.{156 - 6[54 - 2.(9 + 6)]}
= 134 - 2.{156 - 6.[54- 2. 15]}
= 134 - 2.{156 - 6.[54 - 30]}
= 134 - 2.{156 - 6.24]
= 134 - 2.12
= 134 - 24
= 110
a) \(\frac{9}{20}\) c) \(\frac{-55}{4}\)
b) \(\frac{116}{75}\) d) \(\frac{-76}{45}\)
đúng hết đấy nhé mình tính kĩ lắm ko sai đâu
chúc may mắn
a) \(\frac{2}{5}+\left(\frac{3}{4}-\frac{7}{10}\right)\)
\(=\frac{2}{5}+\frac{1}{20}\)
\(=\frac{9}{20}\)
b) \(\frac{-1}{8}-\left(\frac{2}{3}-\frac{11}{12}\right)\)
\(=-\frac{1}{8}-\left(-\frac{1}{4}\right)\)
\(=\frac{1}{8}\)
c) \(\frac{7}{5}-\left(\frac{1}{6}+\frac{9}{10}\right)\)
\(=\frac{7}{5}-\frac{16}{15}\)
\(=\frac{1}{3}\)
d) \(\frac{2}{3}+\left(-\frac{1}{4}\right)+\frac{7}{12}-\left(-\frac{1}{4}\right)-\frac{5}{6}\)
\(=\left(\frac{2}{3}+\frac{7}{12}-\frac{5}{6}\right)+\left(-\frac{1}{4}+\frac{1}{4}\right)\)
\(=\left(\frac{5}{4}-\frac{5}{6}\right)+0\)
\(=\frac{5}{12}\)
e) \(2-\left\{\frac{1}{2}-\left[2-\left(\frac{1}{2}+2\right)-\frac{1}{2}\right]+2\right\}\)
\(=2-\left[\frac{1}{2}-\left(2-\frac{5}{2}-\frac{1}{2}\right)+2\right]\)
\(=2-\left[\frac{1}{2}-\left(-1\right)+2\right]\)
\(=2-\frac{7}{2}\)
\(=-\frac{3}{2}\)
|\(\frac32x\) + \(\frac12\)| = |4\(x\) - 1|
\(\left[\begin{array}{l}\frac32x+\frac12=-4x+1\\ \frac32x+\frac12=4x-1\end{array}\right.\)
\(\left[\begin{array}{l}\frac32x+4x=1-\frac12\\ \frac32x-4x=-1-\frac12\end{array}\right.\)
\(\left[\begin{array}{l}\frac{11}{2}x=\frac12\\ -\frac52x=-\frac32\end{array}\right.\)
\(\left[\begin{array}{l}x=\frac12:\frac{11}{2}\\ x=-\frac32:\frac{-5}{2}\end{array}\right.\)
\(\left[\begin{array}{l}x=\frac12\times\frac{2}{11}\\ x=-\frac32\times\frac{-2}{5}\end{array}\right.\)
\(\left[\begin{array}{l}x=\frac{1}{11}\\ x=\frac35\end{array}\right.\)
Vậy \(x\in\) {\(\frac{1}{11};\frac35\)}
|\(\frac54x\) - \(\frac72\)| - |\(\frac58x\) + \(\frac35\)| = 0
|\(\frac54x\) - \(\frac72\)| = |\(\frac58x\) + \(\frac35\)|
\(\left[\begin{array}{l}\frac54x-\frac72=-\frac58x-\frac35\\ \frac54x-\frac72=\frac58x+\frac35\end{array}\right.\)
\(\left[\begin{array}{l}\frac54x+\frac58x=\frac72-\frac35\\ \frac54x-\frac58x=\frac72+\frac35\end{array}\right.\)
\(\left[\begin{array}{l}\frac{15}{8}x=\frac{29}{20}\\ \frac58x=\frac{41}{10}\end{array}\right.\)
\(\left[\begin{array}{l}x=\frac{29}{10}:\frac{15}{8}\\ x=\frac{41}{10}:\frac58\end{array}\right.\)
\(\left[\begin{array}{l}x=\frac{116}{75}\\ x=\frac{164}{25}\end{array}\right.\)
Vậy \(x\in\) {\(\frac{116}{75}\); \(\frac{164}{25}\)}
a)\(\left(4\frac{5}{37}-3\frac45+8\frac{15}{29}\right)-\left(3\frac{5}{57}-6\frac{14}{29}\right)\)
=\(4\frac{5}{37}-3\frac45+8\frac{15}{29}-3\frac{5}{37}+6\frac{14}{29}\)
=\(\left(4\frac{5}{37}-3\frac{5}{37}\right)+\left(8\frac{15}{29}+6\frac{14}{29}\right)-3\frac45\)
=\(\left\lbrack\left(4-3\right)+\left(\frac{5}{37}-\frac{5}{37}\right)\right\rbrack+\left\lbrack\left(8+6\right)+\left(\frac{15}{29}\right.\right.\)+\(\frac{14}{29})\) -\(\frac{19}{5}\)
=\(1+0+14+1-\frac{19}{5}\)
=\(15+1-\frac{19}{5}\)
=\(16-\frac{19}{5}\)
=\(\frac{80}{5}-\frac{19}{5}\)
=\(\frac{61}{5}\)
\(\left(\frac{3}{8}-\frac{1}{5}-\frac{1}{3}\right)+\left(\frac{5}{8}-1\frac{3}{7}-\frac{4}{7}\right)+\frac{1}{3}\)
\(=\frac{3}{8}-\frac{1}{5}-\frac{1}{3}+\frac{5}{8}-1\frac{3}{7}-\frac{4}{7}+\frac{1}{3}\)
\(=\frac{3}{8}-\frac{1}{5}-\frac{1}{3}+\frac{5}{8}-\frac{10}{7}-\frac{4}{7}+\frac{1}{3}\)
\(=\left(\frac{3}{8}+\frac{5}{8}\right)+\left(\frac{1}{3}-\frac{1}{3}\right)-\left(\frac{10}{7}+\frac{4}{7}\right)-\frac{1}{5}\)
\(=\frac{8}{8}+0-\frac{14}{7}-\frac{1}{5}\)
\(=1+0-2-\frac{1}{5}\)
\(=-1-\frac{1}{5}\)
\(=-1\frac{1}{5}\)