Ta có `: A/B = ( 34/( 7 . 13 ) + 51/( 13 . 22 ) + 85/( 22 . 37 ) + 68/( 37 . 49 ) )/( 39/( 7 . 16 ) + 65/( 16 . 31 ) + 52/( 31 . 43 ) + 26/( 43 . 49 ) )`
`A/B = ( 17/3 . ( 6/( 7 . 13 ) + 9/( 13 . 22 ) + 15/( 22 . 37 )+ 12/( 37 . 49 ) ) )/( 13/3 . ( 9/( 7 . 16 ) + 15/( 16 . 31 ) + 12/( 31 . 43 ) + 6/( 43 . 49 ) )`
`A/B = ( 17/3 . ( 1/7 - 1/13 + 1/13 - 1/22 + 1/22 - 1/37 + 1/37 - 1/49 ) )/( 13/3 . ( 1/7 - 1/16 + 1/16 - 1/31 + 1/31 - 1/43 + 1/43 - 1/49 ) )`
`A/B = ( 17/3 . ( 1/7 - 1/49 ) )/( 13/3 . ( 1/7 - 1/49 ) )`
`A/B = ( 17/3 )/( 13/3 )`
`A/B = 17/3 : 13/3`
`A/B = 17/13`
