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

\[2a(a + b - c) - 2b(a - b - c) + 2c \cdot\]

\[\cdot (a - b + c) = 2a^{2} + 2ab - 2ac - 2ab +\]

\[+ \ 2b^{2} + 2bc + 2ac - 2bc + 2c^{2} =\]

\[= 2a^{2} + \ 2b^{2} + 2c^{2}\]