\(\frac{27}{23}+\frac{5}{21}-\frac{4}{23}+\frac{6}{21}+\frac{1}{2}\)
= \(\left(\frac{27}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{6}{21}\right)+\frac{1}{2}\)
= 1 + \(\frac{11}{21}+\frac{1}{2}\)
= \(\frac{42}{42}+\frac{22}{42}+\frac{21}{42}\)
= \(\frac{85}{42}\)
Tìm x biết:
a) \(-4\frac{3}{5}.2\frac{4}{23}\)≤ x ≤ \(-2\frac{3}{5}:1\frac{6}{15}\)
b) \(-4\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{6}\right)\text{≤ }x\text{ ≤}\frac{-2}{3}.\left(\frac{1}{3}-\frac{1}{2}-\frac{3}{4}\right)\)
1. Tìm x:
a;\(\frac{x+1}{3}=\frac{x-2}{4}\)
b;\(\frac{x-6}{7}+\frac{x-7}{8}+\frac{x-8}{9}=\frac{x-9}{10}+\frac{x-10}{11}+\frac{x-11}{12}\)
c;\(\frac{x+3}{11}+\frac{x+23}{12}=\frac{x+38}{13}+\frac{x+27}{14}\)
1, Tính : P = \(\frac{\frac{1}{2003}+\frac{1}{2004}-\frac{1}{2005}}{\frac{5}{2003}+\frac{5}{2004}-\frac{5}{2005}}-\frac{\frac{2}{2002}+\frac{2}{2003}-\frac{2}{2004}}{\frac{3}{2002}+\frac{3}{2003}-\frac{3}{2004}}\)
2,Biết : 13 + 23 + .......+103 = 3025
Tính S = 23 + 43 + 63 + ....+ 203
\(\frac{4,5:\left[47,375-\left(26\frac{1}{3}-18.0,75\right).2,4:0,88\right]}{17,81:1,37-23\frac{2}{3}:1\frac{5}{6}}\)
c) 7/23 x [(-8/6) - 45/18]
d) 23\(\frac{1}{4}\) : \(\frac{7}{5}\) - 13\(\frac{1}{4}\) : \(\frac{5}{7}\)
e) 25 x 153 / 63 x 102
l) (1/3)10 x (9)25 - (2/3)10 : (4/9)5
i) (-5)7 x (-1/5)7 + 0.56 x (-2)6
Các bạn làm nhanh giùm mình
Tính giá trị biểu thức:
M=\(\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{26}{7}-\frac{13}{11}+\frac{13}{23}}\)+\(\frac{\frac{3}{5}+\frac{3}{13}-0,9}{\frac{7}{91}+0,2-\frac{3}{10}}\)
Tìm x biết :
a) \(\left[\left(6\frac{3}{5}-3\frac{3}{14}\right).2,5\right]:\left(21-1,25\right)=x:5\frac{5}{6}\)
b) \(\left(4-\frac{3}{4}\right):\left(2\frac{1}{3}-1\frac{1}{9}\right)=31x:\left(45\frac{10}{63}-44\frac{25}{84}\right)\)
c) \(\frac{x-1}{x+5}=\frac{6}{7}\)
d) \(\frac{x^2}{6}=\frac{24}{25}\)
e) \(\frac{x-2}{x-1}=\frac{x+4}{x+7}\)
giúp mình nhé 
Thực hiện phép tính:
a,\(\frac{15}{33}+\frac{7}{20}+\frac{18}{33}+\frac{13}{20}\)
b, \(2\frac{1}{2}+\frac{4}{7}:\left(\frac{-8}{21}\right)\)
c, \(\left(\frac{-1}{2}\right)^3+\frac{1}{2}:5\)
chứng minh rằng :
\(\frac{1}{3}+\frac{2}{3^2}+\frac{3}{3^3}+\frac{3}{3^4}+....+\frac{3}{3^{100}}< \frac{3}{21}\)
