OG详解-OG4 数学2 Q3

Choice C is correct. The given expression shows subtraction of two like terms. The two terms can be subtracted as follows: 12x³ -5x³ =(12-5)x³, or 7x³.
Choice A is incorrect and may result from conceptual or calculation errors. Choice B is incorrect. This is the result of adding, not subtracting, the two like terms. Choice D is incorrect and may result from conceptual or calculation errors.