Question

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

Answer 1

$2a(a+b-c)-2b(a-b-c)+2c(a-b+c)=\=2a^2+2ab-2ac\-2ab+2b^2+2bc\+2ac-2bc+2c^2=\=2a^2+2b^2+2c^2$