jmc

We can obtain the graph of $y=g(x)$ by taking the graph of $y=f(x)$ and stretching it horizontally by a factor of 2, then shifting it down by 4 units. Therefore, $g(x)=f\left(\frac{x}{2}\right)-4.$ This means $(a,b,c)=\boxed{\left(1,\frac{1}{2},-4\right)}.$

More generally, for $c>1,$ the graph of $y=f\left(\frac{x}{c}\right)$ is obtained by stretching the graph of $y=f(x)$ horizontally by factor of $c.$