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1) \(\frac{2}{3}+x=-\frac{4}{5}\)
\(x=\left(-\frac{4}{5}\right)-\frac{2}{3}\)
\(x=-1\frac{7}{15}\)
Vậy \(x=-1\frac{7}{15}\)
2) \(\frac{2}{5}-x=-\frac{1}{3}\)
\(x=\frac{2}{5}-\left(-\frac{1}{3}\right)\)
\(x=\frac{11}{15}\)
Vậy \(x=\frac{11}{15}\)
3) \(1-\frac{x}{3}=1\frac{1}{2}\)
\(\frac{x}{3}=1-1\frac{1}{2}\)
\(\frac{x}{3}=-\frac{1}{2}\)
\(\Rightarrow x=\frac{\left(-1\right)\cdot3}{2}\)
\(x=-1\frac{1}{2}\)
4) \(1-\left(\frac{2x}{3}+2\right)=-1\)
\(\frac{2x}{3}+2=1-\left(-1\right)\)
\(\frac{2x}{3}+2=2\)
\(\frac{2x}{3}=2-2\)
\(\frac{2x}{3}=0\)
\(\Rightarrow x=0\)
Vậy \(x=0\)
1. \(\frac{25}{100}x+x-\frac{1}{5}x=\frac{1}{5}\)
\(\Leftrightarrow\frac{1}{4}x+x-\frac{1}{5}x=\frac{1}{5}\)
\(\Leftrightarrow\left(\frac{1}{4}+1-\frac{1}{5}\right)x=\frac{1}{5}\)
\(\Leftrightarrow\frac{21}{20}x=\frac{1}{5}\)
\(\Leftrightarrow x=\frac{1}{5}:\frac{21}{20}\)
\(\Leftrightarrow x=\frac{4}{21}\)
giúp mik nha chiều này 6:00 mik nộp rồi
ai nhanh mik sẽ k cho 3 k
\(2\frac{3}{5}x-\frac{1}{7}=1\frac{9}{35}\)
\(\frac{13}{5}x=\frac{44}{35}+\frac{1}{7}\)
\(\frac{13}{5}x=\frac{7}{5}\)
\(x=\frac{7}{5}:\frac{13}{5}\\ x=\frac{7}{13}\)
1.
A=\(\frac{-5x+-5y+-5z}{21}=\frac{-5\left(x+y+z\right)}{21}=\frac{-5}{21}.x+y+z\)
A= -z+z=0
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1.Vì \(\frac{x}{-2}=\frac{-8}{x}\Rightarrow-2.\left(-8\right)=x.x\)
\(16=x.x\)hay \(4^2=x^2\Rightarrow x=4\)
2. Rút gọn : \(\frac{20}{28}=\frac{5}{7}=\frac{-5}{-7}\)
\(\Rightarrow x=-7\)
3. \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
Mà \(\frac{8}{7}+\frac{11}{5}=\frac{502}{35}\)
\(\Rightarrow x=\frac{234}{35}\)
1) \(\frac{x}{-2}=\frac{-8}{x}\)
\(\Rightarrow x\times x=\left(-2\right)\times\left(-8\right)\)
\(\Rightarrow x^2=16\)
\(\Rightarrow\orbr{\begin{cases}x^2=4^2\\x^2=\left(-4\right)^2\end{cases}\Rightarrow}\orbr{\begin{cases}x=4\\x=-4\end{cases}}\)
Vậy x = 4 hoặc x = -4
2) \(\frac{-5}{x}=\frac{20}{28}\)
\(\Rightarrow\frac{-5}{x}=\frac{5}{7}\)
\(\Rightarrow5\times x=\left(-5\right)\times7\)
\(\Rightarrow5\times x=-35\)
\(\Rightarrow x=\left(-35\right):5\)
\(\Rightarrow x=-7\)
Vậy x = -7
3) \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\Rightarrow\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
\(\Rightarrow\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)
\(\Rightarrow\frac{x}{2}=\frac{117}{35}\)
\(\Rightarrow35x=117\times2\)
\(\Rightarrow35x=234\)
\(\Rightarrow x=234:35\)
\(\Rightarrow x=\frac{234}{35}\)
Vậy \(x=\frac{234}{35}\)
4) \(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)
\(\Rightarrow\frac{x}{5}+\frac{9}{2}=\frac{9}{14}\)
\(\Rightarrow\frac{x}{5}=\frac{9}{14}-\frac{9}{2}\)
\(\Rightarrow\frac{x}{5}=\frac{-27}{7}\)
\(\Rightarrow7x=\left(-27\right)\times5\)
\(\Rightarrow7x=-135\)
\(\Rightarrow x=\left(-135\right):7\)
\(\Rightarrow x=\frac{-135}{7}\)
Vậy \(x=\frac{-135}{7}\)
5) \(\frac{3}{x-5}=\frac{-4}{x+2}\)
\(\Rightarrow\frac{3}{x-5}+\frac{4}{x+2}=0\)
\(\Rightarrow3\left(x+2\right)+4\left(x-5\right)=0\)
\(\Rightarrow3x+6+4x-20=0\)
\(\Rightarrow\left(3x+4x\right)+\left(6-20\right)=0\)
\(\Rightarrow7x-14=0\)
\(\Rightarrow7x=14\)
\(\Rightarrow x=14:7\)
\(\Rightarrow x=2\)
Vậy x = 2
_Chúc bạn học tốt_
\(\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{x.\left(x+2\right)}=\frac{32}{99}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{x}-\frac{1}{x+2}=\frac{32}{99}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{x+2}=\frac{32}{99}\)
\(\Rightarrow\frac{1}{x+2}=\frac{1}{3}-\frac{32}{99}\)
\(\Rightarrow\frac{1}{x+2}=\frac{33}{99}-\frac{32}{99}\)
\(\Rightarrow\frac{1}{x+2}=\frac{1}{99}\)
\(\Rightarrow x+2=99\)
\(\Rightarrow x=99-2\)
\(\Rightarrow x=97\)
Vậy \(x=97\)
\(\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+\frac{2}{7\cdot9}+...+\frac{2}{x\cdot\left(x+2\right)}=\frac{32}{99}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+....+\frac{1}{x}-\frac{1}{x+2}=\frac{32}{99}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{x+2}=\frac{32}{99}\)
\(\Rightarrow\frac{1}{x+2}=\frac{1}{3}-\frac{32}{99}\)
\(\Rightarrow\frac{1}{x+2}=\frac{1}{99}\)
\(\Rightarrow x+2=99\)
\(\Rightarrow x=99-2\)
\(\Rightarrow x=97\)
Vậy x=97
=> I x-3/2 I-4/5=1-29/12
=>I x-3/2 I -4/5= -17/12
=> I x-3/2 I=-37/60
=> ko có giá trị x thõa mãn
<=> \(\left|x-\frac{3}{2}\right|=1-\frac{3}{4}-\frac{5}{3}+\frac{4}{5}\)
<=>\(\left|x-\frac{3}{2}\right|=-\frac{37}{60}\)(vô lý )
=. pt vô nghiệm
Bài làm
\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+.....+\frac{2}{x.\left(x+2\right)}=\frac{2015}{2016}\)
\(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+.....+\frac{1}{x}-\frac{1}{x+2}=\frac{2015}{2016}\)
\(1-\frac{1}{x+2}=\frac{2015}{2016}\)
\(\frac{1}{x+2}=\frac{1}{2016}\)
\(\Rightarrow x+2=2016\)
\(x=2014\)
#thanks#