To determine which graph shows that the linear system \( y = -x + 6 \) and \( 3x + 3y = 18 \) has an infinite number of solutions, we first need to recognize that this occurs when both equations represent the same line.
- The first equation, \( y = -x + 6 \), can be rewritten in standard form as \( x + y = 6 \).
- For the second equation, \( 3x + 3y = 18 \), we can simplify it by dividing everything by 3, which gives us \( x + y = 6 \).
Since both equations simplify to the same line, the linear system has an infinite number of solutions.
Now, looking at the provided graph descriptions:
- First graph: A downward slanting line through points (-6, 0) and (0, -6); this does not represent \( y = -x + 6 \).
- Second graph: A downward slanting line through points (0, 6) and (6, 0); this represents \( y = -x + 6 \).
- Third graph: Two parallel lines; this represents two different equations that do not intersect, thus they do not yield an infinite number of solutions.
- Fourth graph: Two intersecting lines; this represents two different equations that intersect at one point, thus they yield a single solution.
The only graph that shows one line representing both equations is the second graph. Therefore, the correct response is:
A downward slanting line through points (0, 6) and (6, 0) representing the equation \( y = -x + 6 \), confirming that the system has an infinite number of solutions since the other equation simplifies to that.