`x-10/3=7/18+3/5`

`=> x-10/3=89/90`

`=> x=89/90+10/3`

`=> x=389/90`

thanhk you:)

\(x\times\frac{3}{5}-\frac{1}{2}=\frac{4}{5}\)

\(\Rightarrow x\times\frac{6}{10}-\frac{5}{10}=\frac{4}{5}\)

\(\Rightarrow x\times\frac{1}{10}=\frac{4}{5}\)

\(\Rightarrow x=\frac{4}{5}:\frac{1}{10}\)

\(\Rightarrow x=\frac{4}{5}\cdot\frac{10}{1}\)

\(\Rightarrow x=\frac{40}{5}=8\)

Vậy x = 8

\(x\times\frac{3}{5}-\frac{1}{2}=\frac{4}{5}\)

\(x\times\frac{3}{5}=\frac{4}{5}+\frac{1}{2}\)

\(x\times\frac{3}{5}=\frac{13}{10}\)

\(x=\frac{13}{10}:\frac{3}{5}\)

\(x=\frac{13}{6}\)

Lộn :D

\(x\cdot\frac{3}{5}-\frac{1}{2}=\frac{4}{5}\)

\(\Rightarrow x\cdot\frac{3}{5}=\frac{4}{5}+\frac{1}{2}\)

\(\Rightarrow x\cdot\frac{3}{5}=\frac{8}{10}+\frac{5}{10}\)

\(\Rightarrow x\cdot\frac{3}{5}=\frac{13}{10}\)

\(\Rightarrow x=\frac{13}{10}:\frac{3}{5}=\frac{65}{30}=\frac{13}{6}\)

\(x+\frac{3}{7}\times\frac{21}{9}=5\)

\(\Rightarrow x+\frac{3}{7}\times\frac{7}{3}=5\)

\(\Rightarrow x+1=5\)

\(\Rightarrow x=5-1=4\)

\(X+1=5\)

\(X=5-1\)

\(X=4\)

VẬY X=4 

K NHÁ BN

X+\(\frac{3}{7}\)x\(\frac{21}{9}\)=5

X+1=5

X=4

Vay X=.. 

lan sau viet p/s ban nhin o thanh cong cu co cai chu z lon nguoc day bam vao roi chon

Bài làm:

\(\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\right).y=\frac{2}{3}\)

\(\Leftrightarrow\left(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\left(\frac{3-1}{1.3}+\frac{5-3}{3.5}+\frac{7-5}{5.7}+\frac{9-7}{7.9}+\frac{11-9}{9.11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\left(1-\frac{1}{11}\right).y=\frac{4}{3}\)

\(\Leftrightarrow\frac{10}{11}.y=\frac{4}{3}\)

\(\Leftrightarrow y=\frac{4}{3}:\frac{10}{11}=\frac{4}{3}.\frac{11}{10}=\frac{22}{15}\)

Chú ý dấu \(\left(.\right)\)là dấu \(\left(\times\right)\)

Vậy \(y=\frac{22}{15}\)

\(\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\right).y=\frac{2}{3}\)

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

\(\Leftrightarrow\frac{1}{2}.\left(1-\frac{1}{11}\right).y=\frac{2}{3}\)

\(\Leftrightarrow\frac{1}{2}.\frac{10}{11}.y=\frac{2}{3}\)

\(\Leftrightarrow\frac{5}{11}.y=\frac{2}{3}\)

\(\Rightarrow y=\frac{2}{3}:\frac{5}{11}=\frac{22}{15}\)

LƯU Ý:các dấu chấm(.) là dấu nhân ^^.

(\(\frac{1}{1\cdot3}+\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}+\frac{1}{9\cdot11}\)) *y = \(\frac{2}{3}\)

Giải thích kĩ thế :))

Tính

\(\frac{2^7.9^3}{6^5.8^2}=\frac{2^2.2^5.3^5.3}{2^5.3^5.2^6}=\frac{3}{2^4}=\frac{3}{16}\)

Ta có:\(\frac{2^7.9^3}{6^5.8^2}=\frac{2^7.\left(3^2\right)^3}{\left(2.3\right)^5.\left(2^3\right)^2}=\frac{2^7.3^6}{2^5.3^5.2^6}=\frac{2^7.3^6}{2^{11}.3^5}=\frac{3}{16}\)

\(\frac{2^7.9^3}{6^5.8^2}=\frac{2^7.\left(3^2\right)^3}{\left(2.3\right)^5.\left(2^3\right)^2}=\frac{2^7.3^6}{2^5.3^5.2^6}=\frac{2^2.3}{2^6}=\frac{4.3}{64}=\frac{12}{64}=\frac{3}{16}\)
Lâu rồi không làm, không biết có sai sót ở đâu không =)).

2+3/5=3/5

=>2-5-3+3/5=3/5

2-2+3/5=3/5

0+3/5=3/5=3/5 nhe 

Xin lỗi m.n nhé gửi nhầm tí