(五十一分之二+十八分之五)×9×17
=五十一分之二×9×17+十八分之五×9×17
=2/3X9+5/2X17
=6+85/2
=97/2
(2+五分之七)×十四分之五
=2X5/14+7/5X5/14
=5/7+1/2
=17/14