Răspuns :
b) 2x-7x+11x-5x-4x+18x = (2-7+11-5-4+18 )x = 15x
c) 2a+3b-4c+4a-8b+2c-8a+7b+5c =
= -2a+3b-4c-8b+2c+7b+5c =
= -2a+2b-4c+2c+5c =
= -2a+2b+3c
c) 2a+3b-4c+4a-8b+2c-8a+7b+5c =
= -2a+3b-4c-8b+2c+7b+5c =
= -2a+2b-4c+2c+5c =
= -2a+2b+3c