17/8+（14/11+17/11）*11/9
=17/8+14/11*11/9+17/11*11/9
=17/8+14/9+17/9
=（17/8+17/9）+14/9
=1+14/9
=1又14/925/9*12/5-15/225/9*12/5-15/2

=20/3-15/2
=-5/6