Question

упростите выражение 5a(a+b+c)-5b(a-b-c)-5c(a+b-c)

Answer 1

5a(a+b+c)-5b(a-b-c)-5c(a+b-c)=5a²+5ab+5ac-5ab+5b²+5bc-5ac-5bc+5c²=5a²+5b²+5c²