Linear equations in two variables SAT question

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.