Test #4 Section #4 Question #30!
When they say has three real solutions, that means that the and the graph intersect three times. Since must be a horizontal line because k is a constant, all we’re looking for here is where we can draw a horizontal line that will intersect the given graph three times. With that explanation, it might suddenly be obvious that the answer is –3, but in the image below I’ve graphed all answer choices.
See how the line is the only one that intersects the graph three times? That’s why –3 is the answer.