(5/18)/(5/16)+(5/27)/(10/9)
=(5/18)(16/5)+(5/27)(9/10)
=16/18+1/6
=16/18+3/18
=19/18
18X(4/9+7/12)
=18X(16/36+21/36)
=18X(37/16)
=333/8
(2/5)/[(2/3+1/5)X15]
=(2/5)/(10+3)
=(2/5)X(1/13)
=2/65
5/8+4x=7/8
4x=7/8-5/8
4x=1/4
x=1/16
(4/7)X-4/7=3/7
(4/7)X=4/7+3/7
(4/7)X=1
x=7/4
(1-3/4)X=20
(1/4)X=20
x=8018*（9分之4+12分之7）你好像做错了....18X(4/9+7/12)=18X(16/36+21/36)=18X(37/36)=37/2 写错了分母，报歉