c 15: 
​a/ 2/3 + -4/5= -2/15
b/ 5/2-3/2+3 =1+3 = 4
c/ -2/11+35+-9/11 + 2022+2/5 = (-2/11+-9/11) +(3/5+2/5 ) +2022= -1+1+2022= 2022
d/ 22/15. 6/13+2/15.11/13-2/15.4/13= 2/15 . (6/13+11/13-4/13) = 2/15 . 1=2/15
c 16:
a/ x- -5/12=-7/12
x= -7/12 + -5/12
x= -12/12
x= -1
b/ 2/3.x-1/2=5/6
2/3.x= 5/6+1/2
2/3.x= 4/3
x= 4/3:2/3 
x= 4/3.3/2
x= 2
bạn ơi mình làm tắt mong bạn thông cảm