1）5/7-11/14 2）-23 1/ 1/3-3.8) 3）7/9+(1/14-2/7)

1) 5*2/14 - 11/14= 10/14-11/14= -1/14
2) -93/4-(-19/3-19/5)= -93/4+19/3+19/5= -93*15/60 + 19*20/60+ 19*12/60= -1395/60 + 380/60+228/60= -787/60= -13 7/60
3) 7/9+(1/14- 2*2/14)=7/9+ (1/14-4/14)= 7/9-3/14= 7*14/126 - 3*9/126=98/126-27/126= 71/126