SAT Question 744ee7d7: Linear Inequalities answer and explanation with Desmos solution

Choice D is correct. The equation for the line representing the boundary of the shaded region can be written in the form $y=b$, where $(0,b)$ is the y-intercept of the line in the xy-plane. For the graph shown in the xy-plane, the boundary line passes through the points $(-15,36)$ and $(0,36)$. Thus, the equation of the boundary line is $y=36$. Since the shaded region represents all the points on and above this boundary line, it follows that the graph represents all the solutions to the inequality $y\ge 36$.