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4 tháng 8 2016

\(\Leftrightarrow x+1,5x+3,5x=252\)

<=>6x=252

<=>x=42

ủng hộ nhe

4 tháng 8 2016

thank you

7 tháng 8 2017

a ) \(x+x\times\frac{1}{3}\div\frac{2}{9}+x\div\frac{2}{7}=252\)

\(x\times1+x\times\frac{1}{3}\div\frac{2}{9}+x\div\frac{2}{7}=252\)

\(x\times1+x\times\frac{1}{3}\times\frac{9}{2}+x\times\frac{7}{2}=252\)

\(x\times1+x\times\frac{9}{6}+x\times\frac{7}{2}=252\)

\(x\times\left(1+\frac{9}{6}+\frac{7}{2}\right)=252\)

\(x\times6=252\)

\(x=252\div6\)

\(x=42\)

b ) \(\left(3\times x-0,8\right)\div x+14,5=15\)

\(\left(3\times x-0,8\right)\div x=15-14,5\)

\(\left(3\times x-0,8\right)\div x=0,5\)

\(0,8\div x=3-0,5\)

\(0,8\div x=2,5\)

\(x=0,8\div2,5\)

\(x=0,32\)

7 tháng 11 2016

a)

\(x.\frac{7}{9}=\frac{2}{3}+2\frac{1}{2}\)

\(x.\frac{7}{9}=\frac{19}{6}\)

\(x=\frac{19}{6}:\frac{7}{9}\)

\(x=\frac{57}{14}\)

b) \(\frac{5}{7}+x:\frac{9}{4}=\frac{4}{3}\)

\(x:\frac{9}{4}=\frac{4}{3}-\frac{5}{7}\)

\(x:\frac{9}{4}=\frac{13}{21}\)

\(x=\frac{13}{21}.\frac{9}{4}\)

\(x=\frac{39}{28}\)

7 tháng 11 2016

A,27/14

24 tháng 7 2019

\(x+x\times\frac{1}{3}:\frac{2}{9}+x:\frac{2}{7}=252\)

\(x+x\times\frac{3}{2}+x\times\frac{7}{2}=252\)

\(x\times\left(1+\frac{3}{2}+\frac{7}{2}\right)=252\)

\(x\times6=252\)

\(x=252:6\)

\(x=42\)

X + X x \(\frac{1}{3}\)x\(\frac{9}{2}\)+ X x\(\frac{7}{2}\)= 252

X + X x \(\frac{3}{2}\)+ X x \(\frac{7}{2}\)= 252

X x (\(\frac{3}{2}\)\(\frac{7}{2}\)+1) = 252

X x (\(\frac{3}{2}\)\(\frac{7}{2}\)\(\frac{2}{2}\)) = 252

X x 6 = 252

X = 252 : 6

X= 42

Chúc bạn học tốt! ^^

18 tháng 9 2017

a,

x.2/7.3/4=5/21

x.3/14=5/21

x=5/21:3/14

x=10/9

b, 

x.1/2=1/3

x=1/3:1/2

x=2/3

c,

x:4/5=25/8:5/4

x:4/5=5/2

x=5/2.4/5=2

18 tháng 9 2017

A, x= 5/25 : 3/4 : 2/7 = 14/15

B, x=1/3 : 1/2 = 2/3

C, x=(25/8 : 5/4)x4/5 = 5/2 x 4/5 = 2

19 tháng 2 2019

3528/39

20 tháng 2 2019

\(x+x\times\frac{1}{3}\div\frac{2}{9}+x\div\frac{2}{7}=252\)

\(\Leftrightarrow x+x\times\frac{1}{3}\times\frac{9}{2}+x\times\frac{7}{2}=252\)

\(\Leftrightarrow x\left(1+\frac{1}{3}\times\frac{9}{2}+\frac{7}{2}\right)=252\)

\(\Leftrightarrow x\left(\frac{6}{6}+\frac{9}{6}+\frac{21}{6}\right)=252\)

\(\Leftrightarrow x\times\frac{36}{6}=252\)

\(\Leftrightarrow x\times6=252\)

\(\Leftrightarrow x=252\div6\)

\(\Leftrightarrow x=43\)

12 tháng 9 2017

\(x+x\times3:\frac{2}{9}+x:\frac{2}{7}=252\)

\(x+x\times\left(3:\frac{2}{9}\right)+x\times\frac{7}{2}=252\)

\(x+x\times\frac{27}{2}+x\times\frac{7}{2}=252\)

\(x\times\left(1+\frac{27}{2}+\frac{7}{2}\right)=252\)

\(x\times18=252\)

\(x=14\)

3 tháng 7 2018

Câu b:

\(\frac{21}{8}:\frac{5}{6}+\frac{1}{2}:\frac{5}{6}\)

\(\frac{63}{20}+\frac{3}{5}\)

\(\frac{15}{4}\)

7 tháng 7 2018

\(\left(\frac{21}{8}+\frac{1}{2}\right):\frac{5}{6}\)

\(\frac{25}{8}:\frac{5}{6}\)

\(\frac{25}{8}.\frac{6}{5}\)

\(\frac{30}{8}\)

16 tháng 8 2017

Ta có:

\(A=\left(x-\frac{1}{2}\right).\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{90}\right)=\frac{1}{3}\)

\(\Leftrightarrow A=\left(x-\frac{1}{2}\right).\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{9.10}\right)=\frac{1}{3}\)

\(\Leftrightarrow A=\left(x-\frac{1}{2}\right).\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{9}-\frac{1}{10}\right)=\frac{1}{3}\)

\(\Leftrightarrow A=\left(x-\frac{1}{2}\right).\left(\frac{1}{1}-\frac{1}{10}\right)=\frac{1}{3}\)

\(\Leftrightarrow A=\left(x-\frac{1}{2}\right).\frac{9}{10}=\frac{1}{3}\Leftrightarrow x-\frac{1}{2}=\frac{1}{3}.\frac{10}{9}\Leftrightarrow x=\frac{47}{54}\)

\(B=\frac{1}{1.6}+\frac{1}{6.11}+\frac{1}{11.16}+...+\frac{1}{96.101}=\frac{1}{10.x}\)

\(\Leftrightarrow B=\frac{1}{5}.\left(\frac{5}{1.6}+\frac{5}{6.11}+\frac{5}{11.16}+...+\frac{5}{96.101}\right)=\frac{1}{10}-\frac{1}{x}\)

\(\Leftrightarrow B=\frac{1}{5}.\left(\frac{1}{1}-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+\frac{1}{11}-\frac{1}{16}+...+\frac{1}{96}-\frac{1}{101}\right)=\frac{1}{10}-\frac{1}{x}\)

\(\Leftrightarrow B=\frac{1}{5}.\left(\frac{1}{1}-\frac{1}{101}\right)=\frac{1}{10}-\frac{1}{x}\Leftrightarrow B=\frac{1}{5}.\frac{100}{101}=\frac{1}{10}-\frac{1}{x}\)

\(\Leftrightarrow B=\frac{1}{x}=\frac{1}{10}-\frac{20}{101}=-\frac{99}{1010}\Leftrightarrow x=-\frac{1010}{99}\)

16 tháng 8 2017

c) Sai đề nhé bạn vì không có kết quả nên không tìm được x.

d) \(\left(x-5\right).\left(10-9\frac{40}{41}\right):\left(1-\frac{81}{82}\right):\left(1-\frac{204}{205}\right)=2050\)

\(\Rightarrow\left(x-5\right).\frac{1}{41}.82.205=2050\)

\(\Rightarrow\left(x-5\right).2.205=2050\Leftrightarrow x-5=2050:410=5\Leftrightarrow x=10\)