해법
단순화 (a+b+c)5−a5−b5−c5
해법
5a4b+5a4c+10a3b2+10a3c2+20a3bc+10a2b3+10a2c3+30a2bc2+30a2b2c+5ab4+5ac4+20abc3+30ab2c2+20ab3c+5bc4+10b2c3+10b3c2+5b4c
솔루션 단계
(a+b+c)5−a5−b5−c5
(a+b+c)5=(a+b+c)(a+b+c)(a+b+c)(a+b+c)(a+b+c)=(a+b+c)(a+b+c)(a+b+c)(a+b+c)(a+b+c)−a5−b5−c5
(a+b+c)(a+b+c)(a+b+c)(a+b+c)(a+b+c)확대한다:a5+5a4b+5a4c+10a3b2+10a3c2+20a3bc+10a2b3+10a2c3+30a2bc2+30a2b2c+5ab4+5ac4+20abc3+30ab2c2+20ab3c+b5+c5+5bc4+10b2c3+10b3c2+5b4c
=a5+5a4b+5a4c+10a3b2+10a3c2+20a3bc+10a2b3+10a2c3+30a2bc2+30a2b2c+5ab4+5ac4+20abc3+30ab2c2+20ab3c+b5+c5+5bc4+10b2c3+10b3c2+5b4c−a5−b5−c5
a5+5a4b+5a4c+10a3b2+10a3c2+20a3bc+10a2b3+10a2c3+30a2bc2+30a2b2c+5ab4+5ac4+20abc3+30ab2c2+20ab3c+b5+c5+5bc4+10b2c3+10b3c2+5b4c−a5−b5−c5단순화하세요:5a4b+5a4c+10a3b2+10a3c2+20a3bc+10a2b3+10a2c3+30a2bc2+30a2b2c+5ab4+5ac4+20abc3+30ab2c2+20ab3c+5bc4+10b2c3+10b3c2+5b4c
=5a4b+5a4c+10a3b2+10a3c2+20a3bc+10a2b3+10a2c3+30a2bc2+30a2b2c+5ab4+5ac4+20abc3+30ab2c2+20ab3c+5bc4+10b2c3+10b3c2+5b4c