OG详解-OG1 数学2 Q3

Choice B is correct. Adding the second equation in the given system to the first equation in the given system yields 3x + (-3x + y) = 12 +(-6), which is equivalent to y = 6.
Choice A is incorrect and may result from conceptual or calculation errors.
Choice C is incorrect and may result from conceptual or calculation errors.
Choice D is incorrect and may result from conceptual or calculation errors.