Question

Упростите выражение: 2a( a + b - c) - 2b( a- b - c) + 2c( a - b + c )

Answer 1

2a(a+b-c)-2b(a-b-c)+2c(a-b+c)= 2a²+2ab-2ac-2ab+2b²+2bc+2ac-2cb+2c²=2a²+2b²+2c²