SAT Question c651cc56: Linear Functions answer and explanation with Desmos solution

Choice B is correct. A linear function has a constant rate of change, and any two rows of the table shown can be used to calculate this rate. From the first row to the second, the value of $x$ is increased by $2$ and the value of $f(x)$ is increased by $6=4-(-2)$. So the values of $f(x)$ increase by $3$ for every increase by $1$ in the value of $x$. Since $f(2)=4$, it follows that $f(2+1)=4+3=7$. Therefore, $f(3)=7$.