Review question

In the above table the values of $y$ were calculated from a formula $y = Ax^2 + Bx$, where $A$ and $B$ are constants. One of the values of $y$, however, has been deliberately misprinted.
Plot the values of $y/x$ against those of $x$, …
Why does the question ask us to use $y/x$ rather than $y$?