( c - 7 ) ( c² + 7c + 49 ) - ( c - 3 ) c= c ³- 343 - c² + 3c=с³-с²+3с-343
( c - 7 ) ( c² + 7c + 49 ) - ( c - 3 ) c=c^3+7c^2+49c-7c^2-49c-343-c^2+3c=c^3-c^2+3c-343
( c - 7 ) ( c² + 7c + 49 ) - ( c - 3 ) c= c ³- 343 - c² + 3c=с³-с²+3с-343
( c - 7 ) ( c² + 7c + 49 ) - ( c - 3 ) c=c^3+7c^2+49c-7c^2-49c-343-c^2+3c=c^3-c^2+3c-343