Question

Tìm x biết: 1/3*1/x+(1/x+1)*2/5=9/5

 

Answer 1

x = ẩn số

Answer 2

\(\frac{1}{3}\cdot\frac{1}{x}+\left(\frac{1}{x}+1\right)\cdot\frac{2}{5}=\frac{9}{5}\)

\(\frac{1}{3x}+\left(\frac{1}{x}+\frac{x}{x}\right)\cdot\frac{2}{5}=\frac{9}{5}\)

\(\frac{1}{3x}+\frac{1+x}{x}\cdot\frac{2}{5}=\frac{9}{5}\)

\(\frac{1}{3x}+\frac{2\left(1+x\right)}{5x}=\frac{9}{5}\)

\(\frac{1}{3x}+\frac{2+2x}{5x}=\frac{9}{5}\)

\(\frac{5.1}{15x}+\frac{3\left(2+2x\right)}{5x}=\frac{9}{5}\)

\(\frac{5}{15x}+\frac{6+6x}{15x}=\frac{9}{5}\)

\(\frac{5+6+6x}{15x}=\frac{3x\cdot9}{15x}\)

\(\frac{11+6x}{15x}=\frac{27x}{15x}\)

\(\Rightarrow11+6x=27x\)

\(\Rightarrow11=27x-6x\)

\(\Rightarrow11=21x\)

\(\Rightarrow x=\frac{11}{21}\)

\(\Rightarrow S=\left\{\frac{11}{21}\right\}\)