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31 tháng 7 2018

\(\frac{1}{3}\) + \(\frac{5}{6}\)\(\left(x-2\frac{1}{5}\right)\)\(\frac{3}{4}\)

<=> \(\frac{5}{6}\):\(\left(x-2\frac{1}{5}\right)\)\(\frac{3}{4}\)\(\frac{1}{3}\)

<=> \(\frac{5}{6}\) : \(\left(x-2\frac{1}{5}\right)\) = \(\frac{5}{12}\)

<=> \(\left(x-2\frac{1}{5}\right)\) =    \(\frac{5}{6}\) : \(\frac{5}{12}\)

,<=> \(\left(x-2\frac{1}{5}\right)\)=   2 

<=. x = 2 + \(\frac{11}{5}\)

<=> x = \(\frac{21}{5}\)

30 tháng 4 2017

 \(\frac{5}{6}\)\(+\frac{41}{6}+\left(\frac{225}{20}-\frac{37}{4}\right):\frac{25}{3}=\frac{23}{3}+2:\frac{25}{3}=\frac{23}{3}+\frac{6}{25}=\frac{593}{75}\)

11 tháng 6 2020

\(\frac{5}{6}+6\frac{5}{6}.\left(11\frac{5}{20}-9\frac{1}{4}\right):8\frac{1}{3}\)

\(=\frac{5}{6}+\frac{41}{6}.\left(\frac{45}{4}-\frac{37}{4}\right):\frac{25}{3}\)

\(=\frac{5}{6}+\frac{41}{6}.2.\frac{3}{25}\)

\(=\frac{5}{6}+\frac{41}{25}\)

\(=\frac{371}{150}\)

10 tháng 5 2016

\(1-\left(\frac{73}{8}+X-\frac{173}{24}\right):\frac{50}{3}=0\)

\(\Leftrightarrow\left(\frac{73}{8}+X-\frac{173}{24}\right):\frac{50}{3}=1-0\)

\(\Leftrightarrow\left(\frac{73}{8}+X-\frac{173}{24}\right):\frac{50}{3}=1\)

\(\Leftrightarrow\left(\frac{73}{8}+X-\frac{173}{24}\right)=1.\frac{50}{3}\)

\(\Leftrightarrow\left(\frac{73}{8}+X-\frac{173}{24}\right)=\frac{50}{3}\)

\(\Leftrightarrow\frac{73}{8}+X=\frac{50}{3}+\frac{173}{24}\)

\(\Leftrightarrow\frac{73}{8}+X=\frac{191}{8}\)

\(\Leftrightarrow X=\frac{191}{8}-\frac{73}{8}\)

\(\Leftrightarrow X=\frac{59}{4}\)

Dấu \(.\)là dấu X đấy ngen pn!!!!!Nhớ K cko mik nka

9 tháng 9 2017

\(\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{x.\left(x+1\right)}\)\(=\frac{24}{50}\)

\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{x}-\frac{1}{x.1}\)=\(\frac{24}{50}\)

=\(\frac{1}{2}-\frac{1}{x.1}=\frac{24}{50}\)

=\(\frac{1}{x.1}=\frac{1}{2}-\frac{24}{50}\)

=\(\frac{1}{x.1}=\frac{1}{50}\)

\(\Rightarrow\)\(x.1=50\)

\(\Rightarrow x=50\)

11 tháng 4 2020

Câu b

Ta có :x + 3 /1.3  +3/3.5 + 3/5.7+...+3/13.15=2 1/5

X + 2/3.(1-1/3+1/3-1/5+1/5-1/7+...+1/13-1/15)1=11/5

X+2/3.(1-1/15)=11/5

X+ 2/3.14/15=11/5

X + 28/45=11/5

X = 11/5 -28/45

X=71/45

11 tháng 4 2020

Câu a  gợi ý 

1/2-1/3/1/6=0 

1/2- 1/3 - 1/6 ) x (1/2 + 2/3 + 3/4 +4/5 + .......+ 2019 /2020 ) =0 

3/4:x=9/10

X = 3/4:9/10

X = 5/6

13 tháng 7 2018

a) (1,5 . 1,9 - x - 0,5) : 0,25 = 7,5 : 0,125

=> (2,85 - x - 0,5) : 0,25 = 60

=> (2,85 - 0,5) - x = 60 . 0,25

=> 2,35 - x = 15

=> x = 2,35 - 15

=> x = -12,65

Vậy x = -12,65

b) \(1-\left(5\frac{2}{9}+x-7\frac{7}{18}\right)\div2\frac{1}{6}=0\)

\(\Rightarrow\left(5\frac{2}{9}-7\frac{7}{18}+x\right)\div2\frac{1}{6}=1-0\)

\(\Rightarrow\left(\frac{47}{9}-\frac{133}{18}+x\right)\div2\frac{1}{6}=1\)

\(\Rightarrow\frac{-13}{6}+x=2\frac{1}{6}\)

\(\Rightarrow x=2\frac{1}{6}-\frac{-13}{6}\)

\(\Rightarrow x=\frac{13}{6}+\frac{13}{6}\)

\(\Rightarrow x=\frac{26}{6}\)

\(\Rightarrow x=\frac{13}{3}\)

Vậy \(x=\frac{13}{3}\)

c) \(35\left(2\frac{1}{5}-x\right)=32\)

\(\Rightarrow2\frac{1}{5}-x=32\div35\)

\(\Rightarrow\frac{11}{5}-x=\frac{32}{35}\)

\(\Rightarrow x=\frac{11}{5}-\frac{32}{35}\)

\(\Rightarrow x=\frac{9}{7}\)

Vậy \(x=\frac{9}{7}\)

d) \(\frac{4}{3}+\left(x\div2\frac{2}{3}-0,5\right).1\frac{35}{55}=0,6\)

\(\Rightarrow\left(x\div\frac{8}{3}-\frac{1}{2}\right).\frac{18}{11}=\frac{3}{5}-\frac{4}{3}\)

\(\Rightarrow\left(x\div\frac{8}{3}-\frac{1}{2}\right).\frac{18}{11}=\frac{-11}{15}\)

\(\Rightarrow x\div\frac{8}{3}-\frac{1}{2}=\frac{-11}{15}\div\frac{18}{11}\)

\(\Rightarrow x\div\frac{8}{3}-\frac{1}{2}=\frac{-121}{270}\)

\(\Rightarrow x\div\frac{8}{3}=\frac{-121}{270}+\frac{1}{2}\)

\(\Rightarrow x\div\frac{8}{3}=\frac{7}{135}\)

\(\Rightarrow x=\frac{7}{135}.\frac{8}{3}\)

\(\Rightarrow x=\frac{56}{405}\)

Vậy \(x=\frac{56}{405}\)

e) \(1\frac{1}{3}.2\frac{2}{4}\div\frac{5}{6}.1\frac{1}{11}=11-5\div x\)

\(\Rightarrow\frac{4}{3}.\frac{5}{2}\div\frac{5}{6}.\frac{12}{11}=11-5\div x\)

\(\Rightarrow\frac{10}{3}\div\frac{5}{6}.\frac{12}{11}=11-5\div x\)

\(\Rightarrow4.\frac{12}{11}=11-5\div x\)

\(\Rightarrow11-5\div x=\frac{48}{11}\)

\(\Rightarrow5\div x=11-\frac{48}{11}\)

\(\Rightarrow5\div x=\frac{73}{11}\)

\(\Rightarrow x=5\div\frac{73}{11}\)

\(\Rightarrow x=\frac{55}{73}\)

Vậy \(x=\frac{55}{73}\)

a) (1,5 * 1,9 - x - 0,5) : 0,25 = 7,5 : 0,125

(2,85 - x - 0,5) : 0,25 = 60

(2,85 - x - 0,5) = 60 x 0,25

(2,85 - x - 0,5) = 15

2,35 - x = 15

x = 2,35 - 15

x = -12,65

17 tháng 9 2017

tính E phải ko bạn

17 tháng 9 2017

E= 217/292

9 tháng 9 2017

Ta có:

\(\frac{1}{3.7}+\frac{1}{7.11}+\frac{1}{11.15}+...+\frac{1}{x.\left(x+4\right)}=\frac{5}{63}\)

\(=\frac{1}{4}.\left(\frac{4}{3.7}+\frac{4}{7.11}+\frac{4}{11.15}+...+\frac{4}{x.\left(x+4\right)}\right)=\frac{5}{63}\)

\(\Rightarrow\left(\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{15}+....+\frac{1}{x}-\frac{1}{x+4}\right)=\frac{5}{63}:\frac{1}{4}\)

\(\Rightarrow\frac{1}{3}-\frac{1}{x+4}=\frac{20}{63}\Leftrightarrow\frac{1}{x+4}=\frac{1}{63}\Leftrightarrow x=63-4=59\)

9 tháng 3 2022

(1 - 1/2) x (1 - 1/3) x (1 - 1/4) x (1 - 1/5) x (1 - 1/6)

= 1/2 x 2/3 x 3/4 x 4/5 x 5/6

= 1/6 (tử và mẫu triệt tiêu cho nhau)