When you transform a function by writing
![f(x)\mapsto f(x+h)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xrn0qvzpbbh56nl5brqd075yjfwispj8ss.png)
You're translating the function horizontally, h units to to the left if h is positive, and h units to the right if h is negative.
So, for example, given the "standard" parabola
![f(x)=x^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/gd13a4u7jfhi2500q0c3xp0i73vo2psy4f.png)
We have that the child function
has the same shape, but it's translated 3 units to the left.