Answer:
Range = 5 - 29 
Explanation:
a + b > c 
a+c > b
c+b > a 
so 
17+ 12 > c ,,,,,,,,,,,,,,,,,,,,,,,,,,,, so it should be lesser than 17+12 which is 29 
17 +c > 12 ,,,,,,,,,,,,,,,,,,,,,,,,, and it should be greater than 17- 12 = 5 
c+12 > 17 ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, same here, it should be greater than 17- 12 = 5 
So the range is ,
17 + 12
to
17-12 
whcih is - (5 to 29) 
I hope I am right!!!