<=> \(\frac{1}{3}\cdot\left(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3}\right)=\frac{101}{1540}\)
<=>\(\frac{1}{3}\cdot\left(\frac{1}{5}-\frac{1}{x+3}\right)=\frac{101}{1540}\)
<=>\(\frac{1}{5}-\frac{1}{x+3}=\frac{101}{1540}\cdot3=\frac{303}{1540}\)
<=>\(\frac{1}{x+3}=\frac{1}{5}-\frac{303}{1540}=\frac{1}{308}\)
<=>\(x+3=308\)
<=>\(x=305\)
Tim x biet:\(\left(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{65.68}\right)x-\frac{7}{34}=\frac{19}{68}\)
tim x biet :
a )\(\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{x\left(x+3\right)}=\frac{101}{1540}\)
b) \(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{1}{x\left(x+1\right).2}=1\frac{1991}{1993}\)
Tìm X
a) \(\frac{1}{21}\) + \(\frac{1}{28}\) + \(\frac{1}{36}\) +........+\(\frac{2}{x.\left(x+1\right)}\) = \(\frac{2}{9}\)
Chú ý : trong vế có x chỉ có 1 p/s duy nhat có 1 p/s có tử là 2 là p/s cuối
b) \(\frac{1}{5.8}\) + \(\frac{1}{8.11}\) + \(\frac{1}{11.13}\) +.........+\(\frac{1}{x.\left(x+3\right)}\) = \(\frac{101}{1540}\)
c) \(\left(\frac{2}{11.13}+\frac{2}{13.15}+...+\frac{2}{19.21}\right)\)x 462 - [2,04:(x+1,05)]:0.12=19
Mong các bạn giải chi tiết (3 điểm hỏi đáp) Cảm ơn
Tìm x biết:\(\left(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{65.68}\right)x-\frac{7}{34}=\frac{19}{68}\)Trả Lời x =
Tìm x biết : \(\left(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{65.68}\right)x-\frac{7}{34}=\frac{19}{68}\)
Trả lỡi x
\(A=\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{\left(3n-1\right)\left(3n+2\right)}\)
Tính:
\(\left(-1\frac{1}{2}\right).\left(-1\frac{1}{3}\right).....\left(-1\frac{1}{2003}\right).\left(-1\frac{1}{2004}\right)\)
A=\(\frac{15}{2.5}+\frac{15}{5.8}+\frac{15}{8.11}....+\frac{15}{32.35}\)
Rút gọn A= \(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}....+\frac{1}{\left(3n+2\right)\left(3n+5\right)}\)
Thực hiện phép tính
a) \(\frac{5}{16}:0,125-\left(2\frac{1}{4}-0,6\right).\frac{10}{11}\)
b) \(\frac{3}{5.8}+\frac{3}{8.11}+.....+\frac{3}{2012.2015}\)
