Упростите выражение: 6a(a-x+c)+6x(a+x-c)-6c(a-x-c).

\[6a(a - x + c) + 6x(a + x - c) - 6c \cdot\]

\[\cdot (a - x - c) = 6a^{2} - 6ax + 6ac + 6ax +\]

\[+ \ 6x^{2} - 6cx - 6ac + 6cx + 6c^{2} = 6a^{2} + 6x^{2} +\]

\[+ \ 6c²\]