`( \frac{1}{1.2.3} + \frac{1}{2.3.4} + \frac{1}{3.4.5} + ... + \frac{1}{8.9.10} ) . x = \frac{23}{45}`
`\frac{1}{2} ( \frac{1}{1.2} - \frac{1}{2.3} + \frac{1}{2.3} - \frac{1}{3.4} + \frac{1}{3.4} - \frac{1}{4.5} + ... + \frac{1}{8.9} - \frac{1}{9.10} ) . x = \frac{23}{45}`
`\frac{1}{2} ( \frac{1}{2} - \frac{1}{90} ) . x = \frac{23}{45}`
`\frac{22}{45} . x = \frac{46}{45}`
`x = \frac{2070}{990} = \frac{23}{11}`