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tìm x
\(\frac{2017}{2017\cdot\left(x\cdot1\right)}\)=21
dấu chấm là dấu nhân nha ghi đầy đủ cách giải
\(\frac{2017}{2017\cdot\left(x\cdot1\right)}=21\)
\(\Leftrightarrow\frac{1}{x}=21\)
\(\Leftrightarrow x=\frac{1}{21}\)
x + 7/6=16/25
x = 16/25 - 7/6
x = -79/150.
x - 13/6 = 8/5+3/10
x - 13/5 = 19/10
x = 19/10 +13/5
x = 9/2
x : 9/8 = 14/6
x = 14/6 * 9/8
x = 21/8
x * 11/7 = 3/2
x = 3/2 : 11/7
x = 21/22
\(x=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}\)
\(x=\frac{1}{1}-\frac{1}{5}=\frac{4}{5}\)
\(\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}+\frac{3}{512}\)
\(=3.\left(\frac{1}{2}+\frac{1}{2^3}+\frac{1}{2^5}+\frac{1}{2^7}+\frac{1}{2^9}\right)\)
\(=3.A\)với \(A=\frac{1}{2}+\frac{1}{2^3}+\frac{1}{2^5}+\frac{1}{2^7}+\frac{1}{2^9}\)
\(\Rightarrow2^2A=\left(2+\frac{1}{2}+\frac{1}{2^3}+\frac{1}{2^5}+\frac{1}{2^7}\right)\)
\(\Rightarrow2^2A-A=\left(2+\frac{1}{2}+\frac{1}{2^3}+\frac{1}{2^5}+\frac{1}{2^7}\right)-\left(\frac{1}{2}+\frac{1}{2^3}+\frac{1}{2^5}+\frac{1}{2^7}+\frac{1}{2^9}\right)\)
\(\Rightarrow4A-A=2-\frac{1}{2^9}\)
\(\Rightarrow3A=2-\frac{1}{512}=\frac{1023}{512}\Rightarrow A=\frac{1023}{512}:3\)
\(\Rightarrow\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}+\frac{3}{512}=3.\left(\frac{1023}{512}:3\right)=\frac{1023}{512}\)
\(1.a,\frac{5}{7}=\frac{5.9}{7.9}=\frac{45}{63};\frac{4}{9}=\frac{4.7}{9.7}=\frac{28}{63}.\)
\(b,\frac{7}{15},\frac{5}{3}=\frac{5.5}{3.5}=\frac{25}{15}\)
\(c,\frac{11}{12}=\frac{11.4}{12.4}=\frac{44}{48};\frac{7}{48}\)
\(d,\frac{3}{2}=\frac{3.3}{2.3}=\frac{9}{6};\frac{2}{3}=\frac{2.2}{3.2}=\frac{4}{6}\)
\(e,\frac{1}{3}=\frac{1.4}{3.4}=\frac{4}{12};\frac{5}{4}=\frac{5.3}{4.3}=\frac{15}{12};\frac{10}{12}\)
a)\(\dfrac{24}{36}\)=\(\dfrac{8}{12}\)
b)\(\dfrac{14}{56}\)=\(\dfrac{1}{4}\)
c)\(\dfrac{9}{24}\)=\(\dfrac{21}{56}\)
Chúc bạn học tốt!
\(\frac{1}{3}+x\times\frac{2}{7}=\frac{11}{12}\)
\(x\times\frac{2}{7}=\frac{11}{12}-\frac{1}{3}\)
\(x\times\frac{2}{7}=\frac{7}{12}\)
\(x=\frac{7}{12}:\frac{2}{7}\)
\(x=\frac{49}{24}\)
~Moon~
\(\frac{1}{3}+x.\frac{2}{7}=\frac{11}{12}\)
\(x.\frac{2}{7}=\frac{11}{12}-\frac{1}{3}\)
\(x.\frac{2}{7}=\frac{7}{12}\)
\(x=\frac{7}{12}\div\frac{2}{7}\)
\(x=\frac{49}{24}\)