Răspuns :
a) (49a-14b)= 7*( 7a-2b); 7*( 7a-2b) : 7= 7a-2b
b)(121a+55b+77c)= 11*(11a+5b+7c); 11*(11a+5b+7c): 11=11a+5b+7c
b)(121a+55b+77c)= 11*(11a+5b+7c); 11*(11a+5b+7c): 11=11a+5b+7c