\(A=11+14+17+...+62+65\)

Số số hạng của \(A\)là 

\(\left(65-11\right)\div3+1=19\)(số hạng)

Tổng của \(A\)là: 

\(\left(11+65\right)\times19\div2=722\)

Đáp số: 722

\(B=\frac{1}{3}+\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\)

\(B=\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\)

\(B=\left(\frac{3-1}{1.3}+\frac{5-3}{3.5}+.....+\frac{9-7}{7.9}+\frac{11-9}{9.11}\right)\times\frac{1}{2}\)

\(B=\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+.....+\frac{1}{9}-\frac{1}{11}\right)\times\frac{1}{2}\)

\(B=\left(1-\frac{1}{11}\right)\times\frac{1}{2}\)

\(B=\frac{10}{11}\times\frac{1}{2}\)

\(B=\frac{5}{11}\)

\(C=\frac{3}{10}+\frac{3}{40}+\frac{3}{88}+\frac{3}{154}\)

\(C=\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}\)

\(C=\left(\frac{3}{2}-\frac{3}{5}+\frac{3}{5}-\frac{3}{8}+....+\frac{3}{11}-\frac{3}{14}\right)\div3\)

\(C=\left(\frac{3}{2}-\frac{3}{14}\right)\div3\)

\(C=\frac{9}{7}\div3\)

\(C=\frac{3}{7}\)

\(B=\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\)

\(B=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\)

\(B=1-\frac{1}{11}\)

\(B=\frac{10}{11}\)

\(b=\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\)

\(b=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\)

\(b=1-\frac{1}{11}\)

\(b=\frac{10}{11}\)

a) \(15\times\left(\frac{212121}{434343}+\frac{333333}{353535}\right)=15\times\left(\frac{21\times10101}{43\times10101}+\frac{33\times10101}{35\times10101}\right)\)

\(=15\times\left(\frac{21}{43}+\frac{33}{35}\right)=\frac{6462}{301}\)

b) \(\frac{639\times721721}{721\times639639}=\frac{639\times721\times1001}{721\times639\times1001}=1\)

c) \(\frac{327\times412+400}{328\times412-12}=\frac{\left(328-1\right)\times412+400}{328\times412-12}=\frac{328\times412-412+400}{328\times412-12}\)

\(=\frac{328\times412-12}{328\times412-12}=1\)

d) \(9\times\left(\frac{151515}{171717}+\frac{131313}{181818}\right)=9\times\left(\frac{15\times10101}{17\times10101}+\frac{13\times10101}{18\times10101}\right)=9\times\left(\frac{15}{17}+\frac{13}{18}\right)\)

\(=9\times\frac{491}{306}=\frac{491}{34}\)

thank bn

\(=\frac{13\times10101}{15\times10101}+\frac{13\times10101}{35\times10101}+\frac{13\times10101}{63\times10101}+\frac{13\times10101}{99\times10101}\)

\(=\frac{13}{15}+\frac{13}{35}+\frac{13}{63}+\frac{13}{99}=\frac{13}{2}\times\left(\frac{2}{3\times5}+\frac{2}{5\times7}+\frac{3}{7\times9}+\frac{2}{9\times11}\right)\)

\(=\frac{13}{2}\times\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right)=\frac{13}{2}\times\left(\frac{1}{3}-\frac{1}{11}\right)=\frac{13}{2}\times\frac{8}{33}=\frac{52}{33}\)

\(\frac{13.10101}{15.10101}\)+\(\frac{13.10101}{15.10101}\)+\(\frac{13.10101}{63.10101}\)+ \(\frac{13.10101}{99.10101}\)= \(\frac{13}{15}\) +   \(\frac{13}{15}\) + \(\frac{13}{63}\)+  \(\frac{13}{99}\) =\(2\frac{82}{1155}\)

Kết quả của phép tính trên là \(\frac{52}{33}.\)

A)15x2154/1505

=6462/301

B)=103/1031

C)=327/328+400/-12

=727/316

D)=4/5

Bai 2=4 ta thay mau so la 4 nen 43-4=39 va 56-4=52 ta se thay 39/52=3/4.

Giải chi tiết ra chứ

viết mỗi đáp án thôi à giải hẳn ra chứ

131313/151515+131313/353535+131313/636363+131313/999999=13/15+13/35+13/63+13/99

=52/33=1/19/33

​DUYỆT NHÉ

thuy hang beautyful lam chuan

                                      \(\frac{3}{5}x-\frac{13}{9}:\left(\frac{131313}{151515}+\frac{131313}{353535}+\frac{131313}{636363}\right)=-10\)

                                 <=> \(\frac{3}{5}x-\frac{13}{9}:\left(\frac{13}{15}+\frac{13}{35}+\frac{13}{63}\right)=-10\)

                                 <=> \(\frac{3}{5}x-\frac{13}{9}:13:\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}\right)=-10\)

                                 <=> \(\frac{3}{5}x-\frac{1}{9}:\left(\frac{21}{315}+\frac{9}{315}+\frac{5}{315}\right)=-10\)

                                 <=> \(\frac{3}{5}x-\frac{1}{9}:\frac{35}{315}=-10\)

                                 <=> \(\frac{3}{5}x-\frac{1}{9}:\frac{1}{9}=-10\)

                                 <=> \(\frac{3}{5}x-1=-10\)

                                 <=> \(\frac{3}{5}x=-9\)

                                 <=> \(x=-15\)

Vậy x = -15.

\(\frac{3}{5}x-1\frac{4}{9}:\left(\frac{131313}{151515}+\frac{131313}{353535}+\frac{131313}{636363}\right)=-10\)

\(\Leftrightarrow\frac{3}{5}x-\frac{13}{9}:\left(\frac{13}{15}+\frac{13}{35}+\frac{13}{63}=-10\right)\)

\(\Leftrightarrow\frac{3}{5}x-\frac{13}{9}:\left[\frac{13}{2}\left(\frac{2}{15}+\frac{2}{35}+\frac{2}{63}\right)\right]=-10\)

\(\Leftrightarrow\frac{3}{5}x-\frac{13}{9}:\left[\frac{13}{2}\left(\frac{2}{3.5}+\frac{2}{.57}+\frac{2}{7.9}\right)\right]=-10\)

\(\Leftrightarrow\frac{3}{5}x-\frac{13}{9}:\left[\frac{13}{2}\left(\frac{1}{3}-\frac{1}{9}\right)\right]=-10\)

\(\Leftrightarrow\frac{3}{5}x-\frac{13}{9}:\left(\frac{13}{2}.\frac{2}{9}\right)=-10\)

\(\Leftrightarrow\frac{3}{5}x-\frac{13}{9}:\frac{26}{18}=-10\)

\(\Leftrightarrow\frac{3}{5}x-1=-10\)

\(\Leftrightarrow\frac{3}{5}x=-10+1\)

\(\Leftrightarrow\frac{3}{5}x=-9\)

\(\Rightarrow x=-9:\frac{3}{5}\)

\(\Rightarrow x=-15\)

Vậy \(x=-15\)