\(CMR:\frac{1}{11-2}=\frac{12}{111-3}=\frac{123}{1111-4}=\frac{1234}{11111-5}\)
chung to rang 1^11-2 = 12^111-3 = 123^1111-4 = 1234^11111-5
1. Tính \(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+...+\frac{1}{1+2+3+4+...+50}\)
2. Tìm 4 chữ số cuối của tổng \(1+11+111+1111+11111+111111+...+111...11\)(1004 chữ số 1 )
3. Cho \(3^{3x}=\frac{2}{9}\)và \(3^y=27\). Tính \(3^{3x+2y}\)
Trong các câu sau, câu nào là câu đúng?
\(\left(1\right)\frac{1}{11}>\frac{111}{1111}\)
\(\left(2\right)\frac{13}{21}>\frac{15}{23}\)
\(\left(3\right)\frac{31}{29}>\frac{25}{23}\)
\(\left(4\right)\frac{234}{345}>\frac{123}{234}\)
Các bạn có thể trình bày cách so sánh hộ mik đc ko?
tính nhanh
\(5\frac{2}{7}.\frac{8}{11}+5\frac{2}{7}.\frac{5}{11}-5\frac{2}{7}.\frac{2}{11}\)
\(\left(\frac{67}{111}+\frac{2}{33}-\frac{15}{117}\right).\left(\frac{1}{3}-\frac{1}{4}-\frac{1}{12}\right)\)
1) \(5\frac{2}{7}\).\(\frac{8}{11}\)+\(5\frac{2}{7}.\frac{5}{11}+5\frac{2}{7}.\frac{-2}{11}\)
= \(5\frac{2}{7}\).[\(\frac{8}{11}+\frac{5}{11}+\frac{-2}{11}\)]
= \(5\frac{2}{7}\).1
=\(5\frac{2}{7}\)
2)
5 2/7.8/9+5 2/7.5/11-5 2/7.2/11
=5 2/7.(8/11+5/11+2/11)
=5 2/7.15/11
=240/77.
(67/111+2/33-15/117).(1/3-1/4-1/12)
=811/1221.1/12
=811/14652
\(\frac{4}{\frac{111}{\frac{2}{111}+}}+\frac{4}{\frac{123}{\frac{2}{123}+}}+\frac{4}{\frac{999}{\frac{2}{999}}}\)
\(=\frac{2\left(\frac{2}{111}+\frac{2}{123}+\frac{2}{999}\right)}{\frac{2}{111}+\frac{2}{123}+\frac{2}{999}}\)
\(=2\)
\(A=\frac{\frac{4}{111}+\frac{4}{123}-\frac{4}{999}}{\frac{2}{111}+\frac{2}{123}-\frac{2}{999}}\)
\(A=\frac{\frac{4}{111}+\frac{4}{123}-\frac{4}{999}}{\frac{2}{111}+\frac{2}{123}+\frac{2}{999}}\)
\(=\frac{4.\left(\frac{1}{111}+\frac{1}{123}+\frac{1}{999}\right)}{2.\left(\frac{1}{111}+\frac{1}{123}+\frac{1}{999}\right)}\)
\(=\frac{4}{2}=2\)
\(y=\frac{4\frac{6}{11}x11\frac{8}{9}+4\frac{12}{13}:3\frac{2}{5}}{123\frac{34}{45}:21\frac{1}{8}}\)
Lời giải:
\(y=\frac{\frac{50}{11}.\frac{107}{9}+\frac{64}{13}.\frac{5}{17}}{\frac{5569}{45}.\frac{8}{169}}=\frac{1214030}{21879}:\frac{44552}{7605}=\frac{39455975}{4165612}\)
\(\frac{111...1}{tatcaco9chuso1}2\frac{1111...1}{tatcaco9chuso1}\)chia hết cho 11
\(\frac{3}{4}x-14\frac{2}{3}:\left(\frac{11}{15}+\frac{1111}{3535}+\frac{111111}{636363}\right)=12\)
\(\frac{3}{4}x-14\frac{2}{3}:\left(\frac{11}{15}+\frac{1111}{3535}+\frac{111111}{636363}\right)=12\)
\(\frac{3}{4}x-\frac{44}{3}:\left(\frac{11}{15}+\frac{11}{35}+\frac{11}{63}\right)=12\)
\(\frac{3}{4}x-\frac{44}{3}:\frac{11}{9}=12\)
\(\frac{3}{4}x-12=12\)
\(\frac{3}{4}x=12+12\)
\(\frac{3}{4}x=24\)
\(x=24:\frac{3}{4}\)
\(x=32\)
vậy \(x=32\)
ket qua bang 32