**Applications of the Focus Point. **

1. Two pairs of data, **$(1,2)$ and $(2,0)$****determine
a linear function, $f$. **

Find $f(0)$.

**Solution****: Draw the arrows on the Mapping
Diagram and extend them if needed to meet at the Focus Point.**

To find $f(0)$ **on the MD, ****draw the line from the
focus point through $0$ on the Domain Axis . Where the line meets
the Target Axis is $f(0)$. **

**2. Using the same function as in the
previous problem find $a$ where $f(a)= 1$. **

__Solution__: Draw the line from the focus point of $f$ to $1$
on the Target Axis. Where this line meets the Domain Axis, is the
desired value for $a$.