\(\dfrac{5}{6}+\dfrac{3}{2}\times\dfrac{4}{5}\)
= \(\dfrac{5}{6}+\dfrac{6}{5}\)
= \(\dfrac{61}{30}\)
\(\dfrac{5}{6}+\dfrac{3}{2}\times\dfrac{4}{5}\)
= \(\dfrac{5}{6}+\dfrac{6}{5}\)
= \(\dfrac{61}{30}\)
\(\dfrac{6:\dfrac{3}{5}-1\dfrac{1}{6}x\dfrac{6}{7}}{\dfrac{4}{5}x\dfrac{10}{11}+5\dfrac{2}{12}}\)
Bài 1:
a,\(|x-3|+|2-x|=0\)
b,\(\left(2-\dfrac{3}{4}x\right).\left(x+1\right)=0\)
bài 2:
a,A=\(\dfrac{\dfrac{-6}{7}+\dfrac{6}{13}-\dfrac{6}{29}}{\dfrac{9}{7}-\dfrac{9}{13}+\dfrac{9}{29}}\)
b,B=\(\dfrac{\dfrac{2}{15}-\dfrac{2}{21}+\dfrac{2}{39}}{0,25-\dfrac{5}{28}+\dfrac{5}{52}}\)
c,C=\(\dfrac{50-\dfrac{4}{15}+\dfrac{2}{15}-\dfrac{2}{17}}{100-\dfrac{8}{13}+\dfrac{4}{15}-\dfrac{4}{17}}:\dfrac{1+\dfrac{2}{21}-\dfrac{5}{121}}{\dfrac{65}{121}-\dfrac{26}{71}-13}\)
Bài 17 Tìm x biết :
a) \(\dfrac{x}{5}=\dfrac{2}{5}\)
b) \(\dfrac{3}{8}=\dfrac{6}{x}\)
c) \(\dfrac{1}{9}=\dfrac{x}{27}\)
d) \(\dfrac{4}{x}=\dfrac{8}{6}\)
e) \(\dfrac{3}{x-5}=\dfrac{-4}{x+2}\)
g) \(\dfrac{x}{-2}=\dfrac{-8}{x}\)
Tính ( bằng cách thuận tiên nếu có thể )
a, A = \(\dfrac{3^2}{10}\)+\(\dfrac{3^2}{40}\)+\(\dfrac{3^2}{8^8}\)+...+\(\dfrac{3^2}{340}\)
b, A = \(\dfrac{5^2}{1\cdot6}\)+\(\dfrac{5^2}{6\cdot11}\)+...+\(\dfrac{5^2}{26\cdot31}\)
c, A = \(\dfrac{1}{2}\)+\(\dfrac{2}{2\cdot4}\)+\(\dfrac{3}{4\cdot7}\)+\(\dfrac{4}{7\cdot11}\)+\(\dfrac{5}{11\cdot16}\)
d, A = \(\dfrac{3}{54}+\dfrac{5}{126}+\dfrac{7}{249}+\dfrac{8}{609}\)
e, A = \(\dfrac{2}{3}+\dfrac{14}{15}+\dfrac{34}{35}+\dfrac{62}{63}\)
1) Tìm x biết:
\(\left(1-\dfrac{3}{10}-x\right):\left(\dfrac{19}{10}-1-\dfrac{2}{5}\right)+\dfrac{4}{5}=1\)
2) Tính nhanh
a)\(\dfrac{1}{1.2.3}+\dfrac{1}{2.3.4}+\dfrac{1}{3.4.5}+...+\dfrac{1}{10.11.12}\)
b)\(\dfrac{1^2}{1.2}.\dfrac{2^2}{2.3}.\dfrac{3^2}{3.4}.\dfrac{4^2}{4.5}\)
tính B:
B=\(\left(2017-\dfrac{1}{4}-\dfrac{2}{5}-\dfrac{3}{6}-\dfrac{4}{7}-...-\dfrac{2017}{2020}\right):\left(\dfrac{1}{20}+\dfrac{1}{25}+\dfrac{1}{30}+\dfrac{1}{35}+...+\dfrac{1}{10100}\right)\)là:
Các anh chị giải giùm em ::::::::::::))))))))))))))))))))
Bài 1:
a. \(\left(5^{2010}+5^{2012}+5^{2014}\right):\left(5^{2011}+5^{2009}+5^{2007}\right)\)
b. \(\left(-\dfrac{7}{45}\right)-\left(-\dfrac{1}{4}\right)-\left(-\dfrac{3}{5}\right)+\dfrac{1}{12}+\dfrac{2}{3}+\dfrac{1}{39}-\left(-\dfrac{5}{9}\right)\)
\(G=\dfrac{\left(-2\right)}{3}+\dfrac{\left(-5\right)}{7}+\dfrac{2}{3}+\dfrac{\left(-2\right)}{7}\)
\(H=\dfrac{\left(-5\right)}{7}.\dfrac{2}{11}+\dfrac{\left(-5\right)}{7}.\dfrac{9}{11}\)
\(E=\dfrac{5}{7}.\dfrac{12}{11}+\dfrac{5}{7}.\dfrac{12}{11}-\dfrac{5}{7}.\dfrac{17}{11}\)
Tính giá trị biểu thức
2 Trong các ps sau những ps nào bằng nhau
\(\dfrac{15}{60};\dfrac{-7}{5};\dfrac{6}{15};\dfrac{28}{-20};\dfrac{3}{12}\)