1/（4.1+4.09）*2.5
=1/（8.19）x5/2
=100/819x5/2
=250/819
17分之14*73+17分之2*14*6
=14/17x73+14/17x12
=14/17x(73+12)
=14/17x85
=70
54.2-9分之7+4.8-9分之16
=(54.2+4.8)-(7/9+16/9)
=60-23/9
=57又4/9
在右上角点击【评价】,然后就可以选择【满意,问题已经完美解决】了.