\(B=\dfrac{5}{11.16}+\dfrac{5}{16.21}+...+\dfrac{5}{61.66}\)
\(B=\dfrac{5}{5}\left(\dfrac{1}{11}-\dfrac{1}{16}+\dfrac{1}{16}-\dfrac{1}{21}+...+\dfrac{1}{61}-\dfrac{1}{66}\right)\)
\(B=\dfrac{1}{11}-\dfrac{1}{16}+\dfrac{1}{16}-\dfrac{1}{21}+...+\dfrac{1}{61}-\dfrac{1}{66}\)
\(B=\dfrac{1}{11}-\dfrac{1}{66}\)
\(B=\dfrac{6}{66}-\dfrac{1}{66}=\dfrac{5}{66}\)
Tính nhanh:
\(\dfrac{5}{1.6}+\dfrac{5}{6.11}+\dfrac{5}{11.16}+....+\dfrac{5}{96.101}\)
Tính giá trị biểu thức A , biết rằng A = M : N
Mà M = \(\dfrac{\dfrac{1}{99}+\dfrac{2}{98}+\dfrac{3}{97}+\dfrac{4}{96}+...+\dfrac{97}{3}+\dfrac{98}{2}+\dfrac{99}{1}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}+...+\dfrac{1}{100}}\)
N = \(\dfrac{92-\dfrac{1}{9}-\dfrac{2}{10}-\dfrac{3}{11}-...-\dfrac{90}{98}-\dfrac{91}{99}-\dfrac{92}{100}}{\dfrac{1}{45}+\dfrac{1}{50}+\dfrac{1}{55}+...+\dfrac{1}{495}+\dfrac{1}{500}}\)
1. Tính nhanh giá trị biểu thức:
A = \(\dfrac{1}{3}-\dfrac{3}{5}+\dfrac{5}{7}-\dfrac{7}{9}+\dfrac{9}{11}-\dfrac{5}{7}+\dfrac{3}{5}-\dfrac{9}{11}\)
B = \(\dfrac{1}{5}-\dfrac{2}{7}-\left(-\dfrac{2}{3}\right)+\dfrac{1}{42}-\dfrac{1}{4}-\dfrac{13}{28}+\dfrac{2}{15}\)
C = \(\dfrac{1}{50}-\dfrac{1}{50.49}-\dfrac{1}{49.48}-...-\dfrac{1}{3.2}-\dfrac{1}{2.1}\)
D = \(\dfrac{0,75-0,6+\dfrac{3}{7}+\dfrac{3}{13}}{2,75-2,2+\dfrac{11}{7}+\dfrac{11}{3}}\)
giúp mình với
gấp gấp lắm
1/ tìm x
a) \(x.\left(x+\dfrac{2}{3}\right)=0\)
2/tìm giá trị nhỏ nhất của các biểu thức
a) \(\left|x+\dfrac{4}{6}\right|\)
b) \(\left|x-\dfrac{1}{3}\right|\)
3/ tính
a) \(\left(1+2+3+...90\right).\left(12.34-668\right):\left(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}\right)\)
b) \(\dfrac{\dfrac{3}{7}-\dfrac{3}{11}+\dfrac{3}{13}}{\dfrac{5}{7}-\dfrac{5}{11}+\dfrac{5}{13}}+\dfrac{\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}}{\dfrac{5}{4}-\dfrac{5}{6}+\dfrac{5}{8}}\)
Tính giá trị biểu thức:
a,\(A=\dfrac{3^6.45^4-15^{13}.5^{-9}}{27^4.25^3+45^6}\)
b,\(^{B=\dfrac{\left[\left(6,2:0,31-\dfrac{5}{6}.0,9\right).0,2+0,15\right]:12}{\left(2+1\dfrac{4}{11}.0,22:0,1\right).\dfrac{1}{33}}}\)
c,\(C=\dfrac{\left(\dfrac{3}{4}\right)^3+\left(\dfrac{5}{4}\right)^3-5\left(\dfrac{4}{3}-\dfrac{5}{4}\right)}{\left(\dfrac{-5}{8}\right)^2+\left(\dfrac{2}{3}\right)^2-\dfrac{5}{6}}\)
d,\(D=\left[\dfrac{\dfrac{17}{24}.9\dfrac{1}{2}-3\dfrac{1}{4}.\dfrac{17}{24}}{3\dfrac{1}{2}.2\dfrac{13}{36}+2\dfrac{13}{36}.2\dfrac{3}{4}}-\dfrac{1}{5}\right]^{-2}\)
Giúp em với chị @Nhã Doanh ới!!!!!!!!
Mai em phải đi thi rồi :((
Tính giá trị các biểu thức sau:
a, A = \(\left(3\dfrac{5}{6}-1\dfrac{1}{3}\right)\left(3\dfrac{4}{15}-2\dfrac{3}{5}\right)\)
b, B= \(\dfrac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\) c, C = \(\left(1-\dfrac{1}{3}\right)\left(1-\dfrac{1}{6}\right)\left(1-\dfrac{1}{10}\right)\left(1-\dfrac{1}{15}\right)...\left(1-\dfrac{1}{210}\right)\)
tính giá trị các biểu thức
a, A = \(\left(\dfrac{3}{2}-\dfrac{2}{5}+\dfrac{1}{10}\right):\left(\dfrac{3}{2}-\dfrac{2}{3}+\dfrac{1}{12}\right)\)
b, B = \(\dfrac{5}{1.2}+\dfrac{13}{2.3}+\dfrac{25}{3.4}+\dfrac{41}{4.5}+....+\dfrac{181}{9.10}\)
CÁC BẠN ƠI GIÚP MÌNH VS????
HELP ME!!!!!!!!
Tính giá trị biểu thức
B = \(\dfrac{12}{17}.\dfrac{5}{7}-\dfrac{-12}{17}.\dfrac{1}{7}+\dfrac{1}{17.7}.12\)
HELP ME !!!!!!!!!!!!!!!!!!!!!!!
Tính giá trị biểu thức:
B=\(\dfrac{5}{1\times2}+\dfrac{13}{2\times3}+\dfrac{25}{3\times4}+\dfrac{41}{4\times5}+...+\dfrac{181}{9\times10}\)
