SAT Question af2ba762: Linear Functions answer and explanation with Desmos solution

Choice D is correct. Since $2.74$ is a constant term, it represents an actual price of gas rather than a measure of change in gas price. To determine what gas price it represents, find $x$ such that $F(x)=2.74$, or $2.74=2.74-0.19(x-3)$. Subtracting $2.74$ from both sides gives $0=-0.19(x-3)$. Dividing both sides by $-0.19$ results in $0=x-3$, or $x=3$. Therefore, the average price of gas is $$2.74$ per gallon $3$ months after September $1$, $2014$, which is December $1$, $2014$.