Quy đồng mẫu : \(LCM\left(20,11\right)=220\)
\(\Leftrightarrow\dfrac{80}{220}< \dfrac{11\cdot x}{220}< \dfrac{100}{220}\)
\(\Leftrightarrow80< 11\cdot x< 100\)
\(\Rightarrow\) Có hai giá trị của x là \(x=8;x=9\) để \(\dfrac{4}{11}< \dfrac{x}{20}< \dfrac{5}{11}\)
a) Tìm tập hợp số nguyên x ; y sao cho :
\(\left(1\dfrac{3}{4}-\dfrac{6}{4}\right):\left(1\dfrac{1}{5}+2\dfrac{2}{5}+20\%\right)< x< 1\dfrac{1}{5}\cdot1\dfrac{3}{4}+3\dfrac{2}{11}:2\dfrac{3}{21}\)
tìm x
\([\dfrac{6:\dfrac{3}{5}-1\dfrac{1}{16}.\dfrac{16}{7}}{4\dfrac{1}{5}-\dfrac{10}{11}+5\dfrac{2}{11}}-\dfrac{\left(\dfrac{3}{20}+\dfrac{1}{2}-\dfrac{1}{5}\right).\dfrac{12}{49}}{3\dfrac{1}{3}+\dfrac{2}{9}}].x=2\dfrac{23}{96}\)
tìm x:
a) \(-8:\left(4\dfrac{1}{5}x+\dfrac{3}{10}\right)=4\dfrac{4}{9}\)
b) \(4\dfrac{2}{3}-\left(\dfrac{3}{5}:x\right)=-20\%\)
c) \(\left(\dfrac{13}{10}x-15\right).-\dfrac{5}{14}=3\)
d) \(\left(5,5x-44\right):\left(-\dfrac{3}{2}\right)=30\)
e) \(\dfrac{11}{14}:\left(2x+\dfrac{5}{7}\right)=-\dfrac{11}{18}\)
Tìm x biết:
a) \(\dfrac{x+5}{3}\)=\(\dfrac{x-6}{7}\)
b) x - \(\dfrac{20}{11.13}\)-\(\dfrac{20}{13.15}\)-\(\dfrac{20}{15.17}\)-...-\(\dfrac{20}{53.55}\)=\(\dfrac{3}{11}\)
\(\dfrac{1}{3}\)+\(\dfrac{1}{6}\)+\(\dfrac{1}{10}\)+...+\(\dfrac{2}{n\left(n+1\right)}\)=\(\dfrac{2015}{2016}\)
BT3: Tìm x, biết
13) \(\left(-1\dfrac{1}{5}+x\right):\left(-3\dfrac{3}{5}\right)=\dfrac{-7}{4}+\dfrac{1}{4}:\dfrac{1}{8}\)
14) \(\dfrac{11}{13}-\left(\dfrac{5}{42}-x\right)=-\left(\dfrac{15}{28}-\dfrac{11}{13}\right)\)
\(a,-\dfrac{2}{3}.\left(x-\dfrac{1}{4}\right)=\dfrac{1}{3}.\left(2x-1\right)\)
\(b,\dfrac{1}{5}.2^x+\dfrac{1}{3}.2^{x+11}=\dfrac{1}{5}.2^7+\dfrac{1}{3}.2^8\)
\(c,\dfrac{x-19}{345}+\dfrac{x-20}{346}=\dfrac{x-1}{347}+\dfrac{x-22}{348}\)
Bài 1: Thực hiện phép tính:
a, \(\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)
b, \(\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}\)
c, \(\dfrac{\dfrac{1}{9}-\dfrac{5}{6}-4}{\dfrac{7}{12}-\dfrac{1}{36}-10}\)
1. Tìm X
a, \(\left(\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}\right)\cdot10-x=0\)
b, \(\left(\dfrac{1}{11}-\dfrac{1}{21}\right)\cdot462-2.04:\left(x+1.5\right)+11.02=30\)
c, \(\dfrac{4}{3}+x\cdot\dfrac{2}{3}-\dfrac{1}{4}=4\dfrac{5}{12}\)
tìm x thuộc N
\(x-\dfrac{20}{11.13}-\dfrac{20}{13.15}-\dfrac{20}{15.17}-...-\dfrac{20}{53.55}=\dfrac{3}{11}\)
