12а^ + 4ах - 6ах - 2х^ - (12а^ + 12ах - 2ах - 2х^) = 12а^ + 4ах - 6ах - 2х^ - 12 а^ - 10ах + 2х^ = -12ах
12а^ + 4ах - 6ах - 2х^ - (12а^ + 12ах - 2ах - 2х^) = 12а^ + 4ах - 6ах - 2х^ - 12 а^ - 10ах + 2х^ = -12ах