Transforming the graph of a function by shrinking or stretching

So,
From the graph of the function f(x), we can notice it contains the points:
[tex]\begin{gathered} f(2)=-4\to(2,-4) \\ f(-2)=-2\to(-2,-2) \end{gathered}[/tex]If we use the transformation, we obtain the new points:
[tex]\begin{gathered} f(\frac{1}{2}x)\to f(\frac{1}{2}(2))=f(1)=-\frac{7}{2}\to(2,-\frac{7}{2}) \\ f(\frac{1}{2}x)\to f(\frac{1}{2}(-2))=f(-1)=-\frac{5}{2}\to(-2,-\frac{5}{2}) \end{gathered}[/tex]All we need to do to graph the new line is to plot the points:
[tex](2,-\frac{7}{2})\text{ and }(-2,-\frac{5}{2})[/tex]And form a line that passes through them.