Răspuns :
a) a/19 + 11a/19 + 7a/19 = (12a+7a)/19 = 19a/19=a
b) 3a/23 + 17a/23 + 26a/23 = (20a+26a)/23
= 46a/23 = 2a
c) 11x/49 + 13x/49 + 25x/49 = (24x+25x)/49 = 49x/49 = x
d) 15b/7 - 3b/7 - 5b/7 = 12b/7 - 5b/7 = 7b/7 = b
e) 21y/11 - 7y/11 - 3y/11 = 14y/11 - 3y/11 = 11y/11 = y
f) 29c/47 - 21c/47 - 8c/47 = 8c/47 - 8c/47 = 0