Bài 1: Tính giá trị của biểu thức sau
A=1-\(\dfrac{50-\dfrac{4}{2018}+\dfrac{2}{2019}-\dfrac{2}{2020}}{100-\dfrac{8}{2018} +\dfrac{4}{2019}-\dfrac{4}{2020}}\)
B=\(\dfrac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)
C=\(x^{2020}\)-\(y^{2020}\)+\(xy^{2019}\)-\(x^{2019}\).y+2019 biết x-y=0
Mong mn giúp đỡ
1. So sánh
a) \(A=\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{2020}}+\dfrac{1}{2^{2021}}\) và B= \(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{13}{60}\)
b) \(C=\dfrac{2019}{2021}+\dfrac{2021}{2022}\) và \(D=\dfrac{2020+2022}{2019+2021}.\dfrac{3}{2}\)
Tính : S = \(1-\dfrac{1}{2}+\dfrac{1}{3}-\)\(\dfrac{1}{4}+...+\dfrac{1}{2019}-\dfrac{1}{2020}+\dfrac{1}{2021}\)và
P = \(\dfrac{1}{2011}+\dfrac{1}{2012}+\dfrac{1}{2013}+...+\dfrac{1}{2020}+\dfrac{1}{2021}\)
Tính : \(\left(S-P\right)^{2022}\)
Tính biểu thức sau :
\(\left(7-\dfrac{1}{2}-\dfrac{3}{4}\right):\left(5-\dfrac{1}{4}-\dfrac{5}{8}\right)\)
Tính một cách hợp lí :
\(065.78+2\dfrac{1}{5}.2020+0,35.78-2,2.2020\)
Thực hiện phép tính (hợp lí nếu có thể):
a) \(13\dfrac{2}{7}\) : (\(\dfrac{-8}{9}\)) + \(2\dfrac{5}{7}\) : (\(\dfrac{-8}{9}\))
b) (\(\dfrac{-6}{11}\)) . \(\dfrac{7}{10}\) . (\(\dfrac{11}{-6}\)) . (-20)
c) (\(-1\dfrac{1}{2}\)) : \(\dfrac{3}{4}\) . (\(-4\dfrac{1}{2}\))
Thực hiện phép tính (hợp lí nếu có thể):
a) (\(\dfrac{-6}{11}\)) . \(\dfrac{7}{10}\) . \(\dfrac{11}{-6}\) . (-20)
b) (\(-1\dfrac{1}{2}\)) : \(\dfrac{3}{4}\) . \(-4\dfrac{1}{2}\))
c) \(13\dfrac{2}{7}\) : (\(\dfrac{-8}{9}\)) + \(2\dfrac{5}{7}\) : (\(\dfrac{-8}{9}\))
Thực hiện phép tính hợp lý (nếu có thể) :
a) (\(31\dfrac{6}{13}\) + \(5\dfrac{9}{41}\) ) - \(36\dfrac{6}{13}\)
b) \(\dfrac{5}{3}\) +( \(\dfrac{-2}{7}\) ) - (-1,2)
c) 0,25 + \(\dfrac{3}{5}\) - (\(\dfrac{1}{8}\) - \(\dfrac{2}{5}\) + \(1\dfrac{1}{4}\) )
a, \(\left(2x-1\right)\left(x+\dfrac{2}{3}\right)=0\)
b, \(\dfrac{x+4}{2019}+\dfrac{x+3}{2020}=\dfrac{x+2}{2021}+\dfrac{x+1}{2022}\)
tính
A( \(\dfrac{7}{8}-0,25\) ) \(:\left(\dfrac{5}{6}-0,75\right)^2\)
B) \(\dfrac{3}{4}.1\dfrac{4}{9}-\left(\dfrac{-3}{4}\right)\)