Q= 9/40 - 11/60 - 13/84 - 15/112
A= 20/112 + 20/280 + 20/520 + 20/832
dấu / là phân số nha,các bạn giải biểu thức ra giúp mình nha,tks nhìu
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\(\frac{20}{8\cdot14}+\frac{20}{14\cdot20}+\frac{20}{20\cdot26}+\frac{20}{26\cdot32}\)\(\Rightarrow\frac{10}{3}\left(\frac{6}{8\cdot14}+\frac{6}{14\cdot20}+\frac{6}{20\cdot26}+\frac{6}{26+32}\right)\)
\(M=\frac{10}{3}\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)\)\(\Rightarrow M=\frac{10}{3}\left(\frac{1}{8}-\frac{1}{32}\right)=\frac{10}{3}\cdot\frac{3}{32}=\frac{10}{32}\)
k cho mình nha!
\(S=3+\frac{3}{2^2}+\frac{3}{2^3}+...+\frac{3}{2^9}\)=> \(2S=6+\frac{3}{2}+\frac{3}{2^2}+...+\frac{3}{2^8}\)
=>\(2S-S=\left(6+\frac{3}{2}+\frac{3}{2^2}+...+\frac{3}{2^8}\right)-\left(3+\frac{3}{2^2}+\frac{3}{2^3}+...+\frac{3}{2^9}\right)\)
=>\(S=3+\frac{3}{2}-\frac{3}{2^9}\) tự tính nốt
M=20/112+20/280+20/520+20/832
M=20/8.14+20/14.20+20/26.20+20/26.32
M=20/6.(6/8.14+6/14.20+6/20.26+6/26.32)
M=20/6.(1/8-1/14+1/14-1/20+1/20-1/26+1/26-1/32)
M=20/6.(1/8-1/32)
M=20/6.3/32
M=5/16
\(M=\frac{20}{112}+\frac{20}{280}+\frac{20}{520}+\frac{20}{832}\)
\(M=\frac{20}{8.14}+\frac{20}{14.20}+\frac{20}{20.26}+\frac{20}{26.32}\)
\(M=\frac{20}{6}\left(\frac{6}{8.14}+\frac{6}{14.20}+\frac{6}{20.26}+\frac{6}{26.32}\right)\)
\(M=\frac{10}{3}.\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)\)
\(M=\frac{10}{3}.\left(\frac{1}{8}-\frac{1}{32}\right)\)
\(M=\frac{10}{3}.\left(\frac{4}{32}-\frac{1}{32}\right)\)
\(M=\frac{10}{3}.\frac{3}{32}\)
\(M=\frac{5}{16}\)
Chúc bạn học tốt !!!!
Ta có:
\(M=\frac{20}{112}+\frac{20}{280}+\frac{20}{520}+\frac{20}{832}=\frac{20}{8.14}+\frac{20}{14.20}+\frac{20}{20.26}+\frac{20}{26.32}\)
\(\Rightarrow M=20\left(\frac{1}{8.14}+\frac{1}{14.20}+\frac{1}{20.26}+\frac{1}{26.32}\right)\)
\(\Rightarrow M=\frac{20}{6}\left(\frac{6}{8.14}+\frac{6}{14.20}+\frac{6}{20.26}+\frac{6}{26.32}\right)\)
\(\Rightarrow M=\frac{10}{3}\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)\)
\(\Rightarrow M=\frac{10}{3}.\left(\frac{1}{8}-\frac{1}{32}\right)\)
\(\Leftrightarrow M=\frac{10}{3}.\frac{3}{32}=\frac{5}{16}\)
Vậy \(M=\frac{5}{16}\)
\(M=\frac{20}{8.14}+\frac{20}{14.20}+\frac{20}{20.26}+\frac{20}{26.32}\)
\(M=\frac{20}{6}\left(\frac{6}{8.14}+\frac{6}{14.20}+\frac{6}{20.26}+\frac{6}{26.32}\right)\)
\(M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)\)
\(M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{32}\right)\)
\(M=\frac{20}{6}.\frac{3}{32}\)
\(M=\frac{5}{16}\)
k nha
\(M=\frac{5}{28}+\frac{5}{70}+\frac{5}{130}+\frac{5}{208}\)
\(M=\frac{5}{3}\cdot\left(\frac{3}{4\cdot7}+\frac{3}{7\cdot10}+\frac{3}{10\cdot13}+\frac{3}{13\cdot16}\right)\)
\(M=\frac{5}{3}\cdot\left(\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}...\frac{1}{13}-\frac{1}{16}\right)\)
\(M=\frac{5}{3}\cdot\left(\frac{1}{4}-\frac{1}{16}\right)\)
\(M=\frac{5}{3}\cdot\frac{3}{16}\)
\(M=\frac{5}{16}\)
a, \(\frac{51}{60};\frac{52}{60};\frac{41}{60}\)
b, \(\frac{1}{3};\frac{1}{2};\frac{11}{12}=\frac{4}{12};\frac{6}{12};\frac{11}{12}\)
Câu Q có Ước chung lớn nhất là 1680
<=> Q = 378/1680 - 308/1680 - 260/1680 - 225/1680
Q= (378-308-260-255)/1680
Q= -445/1680
Q=-89/336