\(\frac{9.11+19.9}{27.5-27.15}\)\(\frac{23.13+23}{14.47-14}\)
đây là 2 câu nha
Câu 1 :\(\frac{9.11+19.9}{27.5-27.15}\)
Câu 2 : \(\frac{6^5.8^2.21}{49}\)
\(\frac{9.11+19.9}{27.5-27.15}=\frac{9.\left(11+19\right)}{27.\left(5-15\right)}=\frac{9.30}{3.9.\left(-10\right)}=\frac{30}{3.\left(-10\right)}=\frac{30}{-30}=-1\)
Câu 1: \(\frac{9.\left(11+9\right)}{27.\left(5-15\right)}=\frac{9.20}{27.\left(-10\right)}=-\frac{2}{3}\)
Câu 2: Làm biếng giải quá: =\(\frac{1492992}{7}\)
\(\frac{23.13+23}{14.47-14}\)
\(\frac{23.13+23}{14.47-14}=\frac{23.14}{14.46}=1128\)
Cho A = \(\frac{5}{4.3}\) + \(\frac{14}{3.23}\) + \(\frac{16}{23.13}\) + \(\frac{7}{13.46}\) . Tìm A
Tính \(\frac{8}{7.9}^2\). \(\frac{^{^{9^2}}}{8.10}\).\(\frac{10^2}{9.11}\).\(\frac{11^2}{10.12}\).\(\frac{12^2}{11.13}\).\(\frac{13^2}{12.14}\).\(\frac{14^2}{13.15}\)
Có ai làm được không .Mình đang cần gấp . Trình bày dùm mình luôn nha
\(\frac{8^2}{7.9}.\frac{9^2}{8.10}...\frac{14^2}{13.15}\)
\(\frac{8.8}{7.9}.\frac{9.9}{8.10}...\frac{14.14}{13.15}\)
\(\frac{8.9...14}{7.8...13}.\frac{8.9...14}{9.10...15}\)
\(\frac{14}{7}.\frac{8}{15}\)
\(2.\frac{8}{15}\)
\(\frac{16}{15}\)
(8.9.10.11.12.13.14)(8.9.10.11.12.13.14)/7.8.9.10.11.12.13).(9.10.11.12.13.14.15)
=14.8/7.15
=16/15
k cho mình nhá
câu 1 : \(\frac{x+2}{42}+\frac{x+4}{22}=\frac{x+5}{23}+\frac{x+3}{43}\)
câu 2 : \(\frac{x-10}{20}+\frac{x-20}{10}+\frac{x-30}{5}=\frac{x-14}{4}\)
câu 1 : \(\frac{x+2}{42}+\frac{x+4}{22}=\frac{x+5}{23}+\frac{x+3}{43}\)
câu 2 : \(\frac{x-10}{20}+\frac{x-20}{10}+\frac{x-30}{5}=\frac{x-14}{4}\)
B=\(\frac{2}{3.5}\)+\(\frac{2}{5.7}\)+ \(\frac{2}{7.9}\) + \(\frac{2}{9.11}\)
GIÚP MÌNH NHA
CẢM ƠN TRƯỚC NHÉ
\(B=\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+\frac{2}{7\cdot9}+\frac{2}{9\cdot11}\)
\(=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\)
\(=\frac{1}{3}-\frac{1}{11}=\frac{11}{33}-\frac{3}{33}=\frac{8}{33}\)
tính
\(N=\frac{3}{5.7}+\frac{3}{7.9}+\frac{3}{9.11}+...+\frac{3}{197.199}\)
giải giúp mih nha
BÀi này dễ thôi bạn ạ
N=3(1/5.7+1/7.9+.........+1/197.199)
N=3/2( 1/5-1/7+1/7-1/9+1/9-..........+1/197-1/199)
N=3/2(1/5-1/199)
N=3/2.194/995
N=291/995
k đúng cho mình nhé
N=3.1/2.(1/5-1/7+1/7-1/9+1/9-1/11+...+1/197-1/199)
N=3.1/2.(1/5-1/99)
N=3.1/2.94/495
N=3.47/495
N=47/165
N=3/5.7+3/7.9+........+3/197.199
=>N=3/2(2/5.7+2/7.9+.....+2/197.199)
=>N=3/2(1/5-1/7+1/7-1/9+........+1/197-1/199)
=>N=3/2(1/5-1/199)
=>N=3/2x194/995=291/995
\(\frac{2}{9.11}+\frac{2}{11.13}+\frac{2}{13.15}+\frac{2}{15.19}\)
= 1/9 - 1/11 + 1/11 - 1/13 + 1/13 - 1/15 + 1/15 - 1/19
= 1/9 - 1/19
= 10/171
Tk mk nha