If you graphed y = k, it would be a straight horizontal line.
Every place f(x) touches that line, f(x) equals k right there.
At every point that f(x) touches the line y = k, there is a solution for f(x) = k.
The question is basically: where could you put a straight horizontal line so that f(x) touches it 3 times?
Does that help any? If you want more help just say so :)
If you graphed y = k, it would be a straight horizontal line.
Every place f(x) touches that line, f(x) equals k right there.
At every point that f(x) touches the line y = k, there is a solution for f(x) = k.
The question is basically: where could you put a straight horizontal line so that f(x) touches it 3 times?
Does that help any? If you want more help just say so :)