You can
put this solution on YOUR website! .
Horizontal compression of 1/3 is the same as horizontal stretching with coefficient 3.
y = 
.
You multiply "x" by 
.
That is all what you do.
The general rule is that the plot y = f(kx) is the horizontal compression with the coefficient "k" of the plot y = f(x),
for any positive real coefficient "k".
