SAT Question 2e0290c3: Linear Equations In Two Variables answer and explanation with Desmos solution

Choice B is correct. The graph shown is a line passing through the points $\left(0,40\right)$ and $\left(60,0\right)$. 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 $8\left(0\right)+12\left(40\right)=480$, or $480=480$, which is true. Substituting $60$ for $x$ and $0$ for $y$ in the equation $8x+12y=480$ yields $8\left(60\right)+12\left(0\right)=480$, or $480=480$, which is true. Therefore, the equation $8x+12y=480$ represents the relationship between $x$ and $y$.