
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.


Hãy tích cho tui đi
khi bạn tích tui
tui không tích lại bạn đâu
THANKS


1.
Xét TS : đặt 2 ra ngoài ta đc 2 ( 1/3 - 1/13 + 1/4391 )
Xét MS : đặt 4 ra ngoài ta đc 4 ( 1/3 - 1/13 + 1/4391 )
Rút gọn ( 1/3 - 1/13 + 1/4391 ) ở cả TS và MS ta đc kết quả là 2/4 hay 1/2

\(\frac{2}{7}\)+ \(\frac{5}{14}\)+\(\frac{1}{7}\)+ \(\frac{3}{14}\)=\(\frac{4}{14}\)+\(\frac{5}{14}\)+\(\frac{2}{14}\)+\(\frac{3}{14}\)=\(\frac{14}{14}\)=1
469x281+489x719=469x281+(469+20)x719=469x281+469x719+20x719=469x(281+719)+1438=469x1000+1438=469000+1438=470438
a\(\frac{2}{5}\)+\(\frac{5}{14}\)+\(\frac{1}{7}\)+\(\frac{3}{14}\)=\(\frac{53}{70}\)+\(\frac{1}{7}\)=\(\frac{9}{10}\)+\(\frac{3}{14}\)=\(\frac{39}{35}\)
b\(\frac{1995.1997-1}{1996.1995+1994}\)=3984008001
c 469x281+489x719
=(489-469)x(281+719)
=20x1000
=20000

\(B=\)\(\frac{3+33+333+3333+33333}{4+44+444+4444+44444}\)
\(B=\frac{3.1+3.11+3.111+3.1111+3.11111}{4.1+4.11+4.111+4.1111+4.11111}\)
\(B=\frac{3.\left(1+11+111+1111+11111\right)}{4.\left(1+11+111+1111+11111\right)}\)
\(B=\frac{3}{4}\)
\(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}\)
\(A.2=\left(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}\right).2\)
\(A.2=\frac{2}{3}+\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}\)
=>\(A.2-A=\left(\frac{2}{3}+\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}\right)-\left(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}\right)\)
\(A=\frac{2}{3}-\frac{1}{192}\)
\(A=\frac{127}{192}\)
\(\frac{1995}{1997}.\frac{1990}{1993}.\frac{1997}{1994}.\frac{1993}{1995}.\frac{997}{995}\)
Đặt \(C=\frac{1995}{1997}.\frac{1990}{1993}.\frac{1997}{1994}.\frac{1993}{1995}.\frac{997}{995}\)
\(C=\frac{1995.1990.1997.1993.997}{1997.1993.1994.1995.995}\)
\(C=\frac{1990.997}{1994.995}\)
\(C=\frac{995.2+997}{997.2+995}=1\)
\(B=\frac{3+33+333+3333+ 33333}{4+44+444+4444+44444}\)
\(\Rightarrow B=\frac{3\left(1+11+111+1111+11111\right)}{4\left(1+11+111+1111+11111\right)}=\frac{3}{4}\)