Answer
An exponential growth.
Work Step by Step
For $x$.
$1+1=2$
$2+1=3$
$3+1=4$
For $y$.
$17\times 3=51$
$51\times 3=153$
$153\times 3=459$
As $x$ increases by $1$ and $y$ multiplied by $3$.
So, the function is an exponential growth.