Respuesta :

16: 2r - 6 =22 
2r = 22  + 6
2r = 28
r =28/2
r = 14

17: 3g + 7 = 31
3g = 31 - 7
3g = 24
g = 24/3
g= 8

18: 3f - 7 = 38
3f = 38 +7
3f = 45
f = 45/3
f = 15