Question:
Let $X=\{-1,0,3,7,9\}$ and $f: X \rightarrow R: f(x) x^{3}+1$. Express the function $f$ as set of ordered pairs.
Solution:
Given: $f: X \rightarrow R, f(x)=x^{3}+1$
Here, $X=\{-1,0,3,7,9\}$
For $x=-1$
$f(-1)=(-1)^{3}+1=-1+1=0$
For $x=0$
$f(0)=(0)^{3}+1=0+1=1$
For $x=3$
$f(3)=(3)^{3}+1=27+1=28$
For $x=7$
$f(7)=(7)^{3}+1=343+1=344$
For $x=9$
$f(9)=(9)^{3}+1=729+1=730$
$\therefore$ the ordered pairs are $(-1,0),(0,1),(3,28),(7,344),(9,730)$