SAT Question 97eab129: Linear Functions answer and explanation with Desmos solution

Choice B is correct. It's given that the table represents the relationship between the area $x$, in square feet, of the roof of a shopping center and the amount of water $f(x)$, in gallons, drained from the roof into the gutters. Every choice represents this relationship with an equation defining $f$ in the form $f(x)=mx$, where $m$ is a constant rate of change. The value of $m$ can be determined by dividing both sides of the equation by $x$. Each of three pairs of $x$ and $f(x)$ in the table yield $m=1.8$, since $\frac{4,536}{2,520}=1.8$, $\frac{6,804}{3,780}=1.8$, and $\frac{9,072}{5,040}=1.8$. Therefore, the equation $f(x)=1.8x$ could define $f$.