OG详解-OG10 数学2 Q16

Choice B is correct. The graph shown is a line passing through the points (0, 40) and (60, 0). Since the relationship between x and y is linear, if two points on the graph make a linear equation true, then the equation represents the relationship. Substituting 0 for x and 40 for y in the equation in choice B, 8x+12y = 480, yields 8(0)+12(40) = 480, or 480 = 480, which is true.  Substituting 60 for x and 0 for y in the equation 8x+12y = 480 yields 8(60)+12(0) = 480, or 480 = 480, which is true. Therefore, the equation 8x+12y = 480 represents the relationship between x and y.
Choice A is incorrect. The point (0, 40) is not on the graph of this equation, since 40 = 8(0)+12, or 40 = 12, is not true. Choice C is incorrect. The point (0, 40) is not on the graph of this equation, since 40 = 12(0)+8, or 40 = 8, is not true. Choice D is incorrect. The point (0, 40) is not on the graph of this equation, since 12(0)+8(40) = 480, or 320 = 480, is not true.