For the graph of $f$ and $g$: Find the
point at the intersection of the graphs of $f$ and $g$,
$(2,1)$, determine it's first coordinate, $2$, and that is the
desired value for $x$, and its second coordinate, $1$, is the desired value for $y$. 
For the mapping diagram of $f$ and $g$: Find the focus points of $f$, $F= [\frac 1 2, 2]$, and $g$, $G=[1,1]$, on the
mapping diagram. Draw the line through $F$ and $G$, to
find the point of intersection of this line with the X axis, $x=2$,
which is the desired value for $x$ and the Y axis, $y=1$ for the desired value of $y$.
