Tìm x biết
a)\(\dfrac{11}{12}\).x + \(\dfrac{3}{4}\)= -\(\dfrac{1}{6}\)
b)3-\(\left(\dfrac{1}{6}-x\right)\).\(\dfrac{2}{3}\)=\(\dfrac{2}{3}\)
\(A.\dfrac{-15}{28}x\dfrac{7}{25}\\ B.\dfrac{-5}{14}x\dfrac{7}{-3}\\ C.\dfrac{-1}{5}-\dfrac{7}{15}x\dfrac{9}{35}\\ D.\dfrac{-3}{4}-(\dfrac{-1}{2})^2\\ E.\dfrac{-4}{5}-\dfrac{-4}{5}x\dfrac{15}{16}\\F.(\dfrac{3}{4}+\dfrac{-7}{2})x(\dfrac{2}{11}+\dfrac{12}{22})\)
tìm x:
\(\left(1-\dfrac{1}{2}\right)\cdot\left(1-\dfrac{1}{3}\right)\cdot\left(1-\dfrac{1}{4}\right)\cdot...\cdot\left(1-\dfrac{1}{10}\right)=\dfrac{x}{2010}\)
Tính một cách hợp lý:
a\(\left(\dfrac{1}{2}-1\right)\left(\dfrac{1}{3}-1\right)...\left(\dfrac{1}{100}-1\right)\)) \(x:\dfrac{99}{100}:\dfrac{98}{99}:...:\dfrac{2}{3}:\dfrac{1}{2}\)
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) \(\dfrac{\dfrac{1}{9}-\dfrac{5}{6}-4}{\dfrac{7}{12}-\dfrac{1}{36}-10}\)
d) \(\left(\dfrac{1}{2}+1\right)\left(\dfrac{1}{3}+1\right)...\left(\dfrac{1}{99}+1\right)\)
e)
Tìm \(x\), biết :
a) \(x-\dfrac{1}{4}=\dfrac{5}{8}.\dfrac{2}{3}\)
b) \(\dfrac{x}{126}=\dfrac{-5}{9}.\dfrac{4}{7}\)
tìm x
(x+1)+\(\left(x+\dfrac{1}{3}\right)+\left(x+\dfrac{1}{6}\right)+...+\left(x-\dfrac{1}{55}\right)=11\dfrac{9}{11}\)
C=\(\dfrac{2}{15}+\dfrac{2}{35}+\dfrac{2}{63}+...+\dfrac{2}{399}\)
E=\(\dfrac{6}{1.3.7}+\dfrac{6}{6.7.9}+...+\dfrac{6}{13.15.19}\)
F=\(\dfrac{92-\dfrac{1}{9}-\dfrac{2}{10}-\dfrac{3}{11}-...-\dfrac{92}{100}}{\dfrac{1}{9}+\dfrac{1}{10}+...+\dfrac{1}{100}}\)
G=\(10-\dfrac{1}{72}-\dfrac{1}{56}-\dfrac{1}{42}-...-\dfrac{1}{6}-\dfrac{1}{2}\)
Câu 1 :\(\dfrac{-5}{7}.\dfrac{7}{-45}\);\(\dfrac{-3}{10}.\left(-30\right)\);\(-12.\dfrac{-2}{36}\)
Câu 2: \(\dfrac{3}{4}+\dfrac{1}{8}.\dfrac{-16}{5};\dfrac{7}{15}-\dfrac{18}{21}.\dfrac{7}{9}\)
Câu 3: \(\left(\dfrac{-5}{9}+\dfrac{3}{5}\right).\dfrac{3}{10};\left(\dfrac{3}{9}-\dfrac{2}{5}\right).\dfrac{-3}{10}\)
Câu 4: \(\left(\dfrac{3}{7}+\dfrac{1}{3}\right).\left(\dfrac{1}{8}-\dfrac{1}{2}\right);\left(\dfrac{-9}{12}-\dfrac{16}{30}\right).\left(\dfrac{-18}{22}-\dfrac{6}{11}\right)\)
Càn gấp
Tìm x;
a,\(\left(1-\dfrac{1}{3}\right)\)*\(\left(1-\dfrac{1}{6}\right)\)*\(\left(1-\dfrac{1}{10}\right)\)*...*\(\left(1-\dfrac{1}{780}\right)\)*x=1