Tham khảo
` x=\frac{5}{7}.[44+\frac{2}{3}.(44+x)]`
`⇒x=\frac{5}{7}.(44+\frac{88}{3}+\frac{2}{3}x)`
`⇒x=\frac{220}{7}+\frac{440}{21}+\frac{10}{21}x`
`⇒x-\frac{10}{21}x=\frac{1100}{21}`
`⇒\frac{11}{21}x=\frac{1100}{21}`
`⇒x=\frac{1100}{21}:\frac{11}{21}`
`⇒x=100`
`\text{©CBT}`