`3x - 15/( 5.8) - 15/( 8.11) - 15/( 11.14) - ..... - 15/( 47.50)= 2 1/10`
`3x - (15/( 5.8) + 15/( 8.11) + 15/( 11.14) + ..... + 15/( 47.50))= 21/10`
`3x - [15/3 . (3/( 5.8) + 3/( 8.11) + 3/( 11.14) + ..... + 3/( 47.50))]= 21/10`
`3x - [15/3 . ( 1/5 - 1/8 + 1/8 - 1/11 + 1/11 - 1/14 + .... + 1/47 - 1/50)] = 21/10`
`3x - [ 15/3 . ( 1/5 - 1/50)] = 21/10`
`3x - [ 15/3 . 9/50] = 21/10`
`3x - 9/10 = 21/10`
`3x = 21/10 + 9/10`
`3x = 3`
`x = 3 : 3`
`x = 1`
Vậy `x = 1`